A method for the manufacture of composite cans and a composite can made by the method

ABSTRACT

A method for manufacturing and filling a composite can ( 201 ), the method comprising: —forming a tubular body ( 203 ) by bending a body blank ( 16 ) and bringing two opposing edges of the body blank ( 16 ) together in an end-to-end join; —sealing the join by welding a sealing strip ( 214 ) over the join, thereby forming an intermediate can ( 403; 503 ); —sealing a top opening ( 211 ) by attaching a top sealing member ( 227 ) across the top opening ( 211 ); —applying a top rim ( 223 ) to the intermediate can ( 403; 503 ) by welding an inserted part of the top rim ( 223 ) to the inner surface of the tubular body ( 203 ); —turning the intermediate can ( 403; 503 ) upside-down and placing the intermediate can ( 403; 503 ) on a conveyor ( 2   a ) with the top rim ( 223 ) resting on the conveyor ( 2   a ); filling the intermediate can ( 403; 503 ) through the bottom opening ( 213 ); —sealing the bottom opening ( 213 ) of the tubular body ( 203 ) by attaching a bottom sealing member ( 215 ) across the bottom opening ( 213 ); —turning the intermediate can ( 403; 503 ) to bring the top rim ( 223 ) in an upward-facing position; —attaching a reclosable lid ( 221 ) at the top end of the tubular body ( 203 ). The intermediate can is kept in a protective gas atmosphere from said filling of said intermediate can until said bottom opening ( 213 ) of said tubular body ( 203 ) has been sealed. An assembly line ( 1 ) for manufacturing and filling of composite cans ( 201 ) is also disclosed.

TECHNICAL FIELD

The disclosure pertains to a method for manufacturing composite cans and packaging of dry or moist goods in the composite cans. The composite cans as disclosed herein comprise a carton body made from a carton based laminate which in addition to a carton core layer may include one or more outer polymeric layers and a metallic foil layer such as an aluminum layer. Furthermore the composite cans include additional can components such as a top sealing member, a bottom sealing member, a top rim, a reclosable lid and, optionally, a bottom rim.

BACKGROUND

Composite carton based cans for packaging of moisture and air sensitive particulate or granulated goods such as baby food, coffee, tea, cereals, tobacco, etc. are well known in the art. In the area of packaging of consumer goods, and in particular consumer goods which is packaged in relatively rigid composite cans which serve as protective transport and storage containers at the retail end and as storage and dispensing containers at the consumer end, the different functions of the composite cans may result in conflicting demands on their design. For economic and environmental reasons, the amount of material required for producing the composite cans should be as small as possible while still providing the composite can with sufficient rigidity and shape stability. At the retail end there is a desire that the composite cans allow efficient and space-saving transport and storage and that they are stackable.

Carton based cans generally suffer from low shape stability in the carton body, which has proven to be a particular problem during manufacturing and filling of the cans before they are finally sealed. While providing sufficient shape stability and protection of packaged goods in a filled and fully assembled composite can, the relatively thin carton body material may suffer damage when exposed to the forces exerted on the carton body during production and filling of the composite cans. Built-in tensions in the stiff carton material cause the tubular bodies which are formed from rectangular carton blanks to deviate from an intended body shape, making the tubular bodies difficult to process at high speeds in a manufacturing machine. Tubular bodies which deviate from an intended shape are more prone to being damaged by grippers, transporters and other equipment in the manufacturing line. Such damage may lead to an undesirable high waste ratio, as the damaged tubular bodies would have to be discarded. By way of example, tubular bodies which are transported on a conveyor belt may accumulate on the conveyor into a tightly packed line of tubular bodies being pressed against each other, causing the tubular bodies to assume a deformed configuration with a shortened extension in the transport direction and an increased extension perpendicular to the transport direction. Tubular bodies which are deformed in this manner may get stuck in the machine or may be difficult to grip and reposition with a gripper. Furthermore, it may be difficult to attach elements such as a top sealing member, a bottom sealing member, a plastic rim, etc. without damaging the exposed end edge of the tubular body. In order to minimize the risk of deforming or damaging the tubular bodies during manufacture, the manufacturing speed may need to be lowered which leads to a less efficient production of the composite cans than would have been preferred.

Accordingly, there is a need for a low cost, high-speed production process for a composite can made from commonly available materials which process can be run with minimal waste in the production line.

An object of the present disclosure is to overcome or ameliorate at least one of the disadvantages of the prior art, or to provide a useful alternative.

SUMMARY

The above object may be achieved with a method in accordance with claim 1 and the assembly line in accordance with claim 10. Further embodiments are set out in the dependent claims, in the following description and in the drawings.

As set out herein, there is provided a method for manufacturing composite cans and packaging of dry or moist goods in the composite cans, the method comprising:

-   -   picking a body blank from a pile of body blanks and transferring         the body blank to a body forming station;     -   forming a tubular body by bending the body blank and bringing         two opposing edges of the body blank together in an end-to-end         join, the join extending in a height direction of the tubular         body;     -   sealing the join by welding a sealing strip over the join on an         inner surface of the tubular body, thereby forming an         intermediate can;     -   transferring the intermediate can to a top sealing station;     -   sealing a top opening at a top end of the tubular body by         welding a peripheral flange of a top sealing member to the inner         surface of the tubular body at a distance from a top end edge of         the tubular body;     -   transferring the intermediate can to a top rim application         station;     -   applying the top rim to the intermediate can by inserting at         least a lower part of the top rim into the top opening, above         the top sealing member;     -   welding the inserted part of the top rim to the inner surface of         the tubular body;     -   transferring the intermediate can to a conveyor and placing the         intermediate can on the conveyor with the top rim resting on the         conveyor and a bottom opening at a bottom end of the tubular         body facing upward in the vertical direction;     -   transferring the intermediate can to a filling unit;     -   filling the intermediate can with said dry or moist goods         through the bottom opening of the tubular body;     -   subjecting said intermediate can to a protective gas atmosphere         either during said filling of said intermediate can or by         introducing said filled intermediate can into a vacuum chamber         to draw off air;     -   transferring said filled intermediate can to a sealing unit,         said filled intermediate can being transported to said sealing         unit in a closed conveying system while maintaining said         protective gas atmosphere;     -   sealing said bottom opening of said tubular body by welding a         peripheral flange of a bottom sealing member to said inner         surface of said tubular body at a distance from a bottom end         edge of said tubular body, sealing of said bottom opening being         carried out while maintaining said protective gas atmosphere;     -   turning the filled and bottom sealed intermediate can to bring         the top rim in an upward-facing position in the vertical         direction and transferring the intermediate can to a lid         attachment unit;     -   attaching a reclosable lid at the top end of the tubular body         with an inner surface of the reclosable lid in direct contact         with an upper surface of the top rim.

The intermediate can is kept in a protective gas atmosphere from when the protective gas atmosphere is created in conjunction with the filling of the intermediate can until the bottom opening of the tubular body has been sealed. Thereby air contact between the filled goods in the open intermediate container may be prohibited until the goods has been safely enclosed in the composite can. A further technical effect is that the atmosphere in the sealing station and the sealing step can be extremely well controlled as there is no need of removing air from the filled open containers before sealing the containers. This has been found to be a considerable advantage as pressure differences in the sealing step may negatively affect the sealing process by causing turbulence in the packaged material. Such turbulence may result in powdery material being captured in the seals and potentially compromising the tightness of the seals.

The steps of:

-   -   transferring the intermediate can to a top rim application         station;     -   applying the top rim to the intermediate can by inserting at         least a lower part of the top rim into the top opening, above         the top sealing member;     -   welding the inserted part of the top rim to the inner surface of         the tubular body;     -   transferring the intermediate can to a conveyor and placing the         intermediate can on the conveyor with the top rim resting on the         conveyor and a bottom opening at a bottom end of the tubular         body facing upward in the vertical direction;

are optional to composite cans having a top closure with a lid formed from paperboard components.

As disclosed herein, a longitudinal axis of the intermediate can may be arranged in a generally vertical direction with the top end of the tubular body directed upwards in the vertical direction during transfer of the intermediate can from the top sealing station to the top rim application station.

In the method as disclosed herein, the top end edge of the tubular body is directed upward in the vertical direction and the bottom end edge of the tubular body is directed downward in the vertical direction during application and attachment of the top sealing member and a top rim at the top opening of the tubular body. Thereafter, the intermediate can comprising the tubular body, the top sealing member and the top rim, is turned upside-down so that the top end edge is directed downward in the vertical direction and the bottom end edge is directed upward in the vertical direction. The intermediate can with the top rim attached may be turned in a rim applicator or in a conventional turning apparatus downstream of the rim applicator.

By attaching a top rim to the tubular body and turning the intermediate can upside-down before transporting the intermediate can to the filling unit, the intermediate can will rest with the durable top rim on the conveyor during transfer to the filling unit.

By attaching the top sealing member before filling the can, the risk of finding residues of packaged material outside the top sealing member in the upper end of the can is eliminated as is the risk that particulate material contaminates the weld area and negatively affects the quality of the top sealing member seal.

The top rim is preferably a polymeric component having higher rigidity than the tubular body. The top rim may suitably be made by injection molding. The top rim contributes to shape and stabilize the flexible paperboard body and constitutes a protection for the top end edge of the tubular body. The top rim brings the container body wall to conform to the contour of the top rim and to be provided with a desired predetermined and stable shape.

The weld seal between the top rim and the tubular body may be formed by any suitable method such as by high frequency induction welding. In order to achieve a tight seal, the weld seal is preferably a continuous seal extending around the top opening to produce a moisture proof and preferably gas-tight seal. In the composite cans produced according to the method as disclosed herein, high frequency induction welding is a preferred method for attaching can components such as the body sealing strip, top and bottom rims, and the top and bottom sealing members.

By joining the top rim to the inner surface of the tubular body by means of welding, it is possible to obtain a tighter and slimmer attachment of the top rim to the tubular body than when using an adhesive attachment which was previously common in the art. As set out herein, the welded top rim is preferably a plastic rim and is arranged to extend parallel to the material in the tubular body, from the inner surface of the tubular body to an inner surface of a lid. The top rim is more rigid than the carton based material in the tubular body and constitutes a shape stable continuation of or supplement to the upper end of the tubular body and provides a first abutment surface which is resistant to deformation when pressed against a second abutment surface on an inner surface of the reclosable lid.

Thereby, the composite can may be repeatedly opened and closed with a high level of tightness even after a first opening of the can by a consumer and after breaking or removal of the top sealing member.

Thus, the top rim constitutes a rigid and shape stable part at the top end of the tubular body which may form a tight seal against the inner surface of the lid.

The top rim is preferably welded to the inner surface of the tubular body, such that an upper part of the top rim extends past the top end edge of the tubular body.

The top rim may be a profiled element comprising a circumferential flange extending outwardly from an upper edge of the lower part of the top rim, the top rim being applied to the intermediate can with the circumferential flange covering an upper end edge of the tubular body. The circumferential flange constitutes a rigid protection of the carton material in the top end edge of the tubular body.

A top rim which is attached to the tubular body with a part of the top rim extending out of the top opening in the tubular body in the height direction of the tubular body, forms a rigid, wear resistant and shape stable support on which the intermediate can may rest after having been turned 180° to place it upside-down on a conveyor for transfer to a filling unit. The intermediate cans may form tightly packed queues or slide on the conveyor belt without causing deformation of the carton material in the tubular bodies or damage to the top end edge of the tubular body.

The top rim may have any suitable cross-sectional profile as long as it can be fitted with at least a part of the top rim inside the top opening. The lower part of the top rim may have different thickness in different parts of the top rim. It may be preferred that no part of the top rim is arranged to extend downward on the outer surface of the body tube. A top rim having a generally I-shaped or L-shaped profile may be preferred as it can be readily inserted into the top opening and be attached to the inner surface of the tubular body by welding and application of pressure perpendicular to the inner surface of the tubular body.

As set out herein, the carton body is supported and protected by the top rim during subsequent process steps without risking damage to an exposed carton edge. The top rim provides support and protection for the intermediate can during process steps such as filling and sealing of the bottom opening, de-gassing, etc., which steps may be performed while the intermediate can is resting on the top rim.

The top rim makes it possible to fill the container from the bottom end, after the top sealing member has been applied at the top opening. If instead applying a top end sealing member after the composite can has been filled with contents in the form of particles or granules, the turbulence created when the top sealing member is pushed into the container body may cause some of the particles or granules to escape out of the tubular body and to end up on the outside of the top sealing member, in the space between the top sealing member and the top end edge of the tubular body. A user opening a composite can and finding the exposed top sealing member to be soiled by the packaged material, will generally consider the can to be less hygienic than would have been desired. Furthermore, some of the packaged material may be trapped in the weld seal between the top sealing member and the inner surface of the tubular body, making the seal less tight than desired and making it difficult to accurately control the strength of the seal.

The method as disclosed herein may further comprise:

-   -   applying a bottom rim to the bottom end of the bottom sealed         intermediate can;     -   placing the bottom sealed intermediate can on a conveyor band         with the bottom rim resting on the conveyor band during the         transfer of the intermediate can to the lid attachment unit.

The bottom rim is applied in the form of a closed loop extending in a bottom loop plane and having an outer contour and an inner contour and a height in a height direction perpendicular to the bottom loop plane. The bottom rim has an upper rim part and a lower rim part in the height direction of the bottom reinforcing rim. The bottom rim may be applied by:

-   -   inserting the top rim part of the bottom rim and optionally also         the lower rim part of the bottom rim into the tubular body at         the bottom end edge with a lower end edge of the bottom         reinforcing rim being outside of the container body or flush         with the bottom end edge of the tubular body; and     -   attaching the bottom rim to the inner surface of the tubular         body, the attachment preferably being made by welding, such as         by high frequency induction welding.

The advantages of providing the composite can with a bottom rim are similar to those obtained with the top rim. In the intermediate can which has been filled from the bottom end and sealed with a bottom sealing member the bottom rim enhances shape stability at the bottom end of the tubular body and protects the bottom end edge of the carton material in the tubular body from wear when the filled and bottom sealed intermediate can is transported on a conveyor while standing on the bottom rim. In the completely assembled composite can, the bottom rim continues to be a support element which protects the carton material at bottom end of the composite can from moisture which may be present on a counter-top or other surface on which the can is placed by a user. The bottom rim may further form a rigid and shape stable support element cooperating with mating stacking elements at the upper part of another composite can when stacking the composite cans on top of each other.

After application of the bottom sealing member to the filled intermediate can, the sealed and filled intermediate can may be turned 180° in the sealing unit or in a conventional turning apparatus downstream of the sealing unit.

The method as disclosed herein may involve that two or more intermediate cans, such as four intermediate cans, are processed simultaneously during one or more process steps such as:

-   -   sealing the top opening;     -   applying the top rim;     -   welding the top rim;     -   turning the intermediate can 180°;     -   filling the intermediate can;     -   sealing the bottom opening;     -   turning the filled and bottom sealed intermediate can 180°; and     -   attaching the reclosable lid.

Disclosed herein is also an assembly line for manufacturing of composite cans and filling of dry or moist goods in the composite cans e.g. in accordance with the method as disclosed herein. The assembly line comprises a plurality of machine units connected by conveyors wherein the machine units comprise:

-   -   a body forming unit;     -   a filling unit;     -   a sealing unit; and     -   a lid attachment unit.

In the assembly line as disclosed herein, a gas box may be arranged between the filling unit and the sealing unit.

The body forming unit of the assembly line may include:

-   -   a body blank picking station;     -   a body forming station;     -   a top sealing station; and     -   a top rim application station.

The sealing unit of the assembly line may include a can sealing station and optionally a rim application station.

Any machine unit of the assembly line may be at least partly arranged in an external housing. Furthermore, any machine unit or part of a machine unit may be arranged to operate in a modified gas atmosphere also referred to herein as a protective gas atmosphere in the external housing. As disclosed herein, the sealing unit may be arranged in an external housing and may be arranged to operate in a protective gas atmosphere in the external housing. In addition, any can component applicator as disclosed herein may be arranged at least partly in an internal housing inside an external housing.

The method as disclosed herein may comprise a degassing step which is performed in conjunction with the filling step. The degassing step may comprise supplying a protective gas to the product flow in the filling step. The protective gas may be nitrogen, carbon dioxide or a mixture of nitrogen and carbon dioxide. The protective gas may be blown into the flow of dry or moist product during filling of the intermediate can, before the product flow reaches the inner compartment in the intermediate can.

Alternatively or in addition thereto, sealing of the bottom opening may be carried out in a protective gas atmosphere. When the product flow is treated with protective gas in the filling step, the filled intermediate cans are preferably conveyed to the closing step in the sealing unit while maintaining the protective atmosphere, e.g. by moving the intermediate cans through a tunnel filled with protective gas. Alternatively, the filled intermediate cans may be introduced into a vacuum chamber to draw off air whereafter the filled intermediate cans are subjected to a protected atmosphere and sealed.

Application of can components such as a top sealing member, a bottom sealing member, a top rim and a bottom rim may be performed using an attachment unit comprising a welding unit, such as a high frequency induction welding unit, which is configured to fasten the component to the tubular body during production of the composite can. The welding unit may comprise an inductive welding energy generator for softening or melting a weldable layer that forms part of the tubular body and/or the applied can component.

The apparatus may further comprise transporting means configured to transport a flow of intermediate cans to and from the attachment unit. The transporting means may comprise, in sequence, a feeding arrangement, a main conveyor member and a movable gripping arrangement. The feeding arrangement may be configured to transfer intermediate cans one by one in a continuous manner to the main conveyor member and the gripping arrangement may be configured to transfer intermediate cans from the main conveyor member to the welding unit. The apparatus may be arranged such that during normal operation of the apparatus, the intermediate cans line up close to each other at an upstream side of the feeding arrangement, the feeding arrangement being configured to separate adjacent intermediate cans from each other in a feeding direction by increasing the feeding speed of each individual intermediate can along the feeding arrangement and thereby increasing the distance between adjacent intermediate cans fed along the feeding arrangement. The main conveyor member may be configured to operate at a transport speed that approximately corresponds to, and is uniform in relation to, a discharge speed of the intermediate cans when fed out from the feeding arrangement such that intermediate cans transferred to and along the main conveyor member remain separated. The movable gripping arrangement may be configured to grip at least two intermediate cans, such as four intermediate cans, and to transfer these intermediate cans simultaneously from the main conveyor member to the attachment unit, the attachment unit preferably being configured to simultaneously fasten the can component to each of the simultaneously transferred intermediate cans.

The feeding arrangement may comprise a feed screw member provided with an increasing pitch such that the feeding speed of each individual intermediate can, as well as the distance between adjacent intermediate cans, increase in correspondence with the increasing pitch when the intermediate cans are transported by the feed screw member. Such a feed screw member creates defined distances between the intermediate cans, allowing for a controlled positioning and proper gripping of the intermediate cans.

The feed screw member allows for a controlled feeding speed at the inlet of the feed screw member. By adjusting this inlet speed in relation to the speed at which the intermediate cans are transported towards the feed screw member, for instance by letting the inlet speed be only slightly lower than the transport speed of a conveyor belt arranged to transport the intermediate cans to the feed screw member, it can be prevented that filled open intermediate cans collide at high speed with a slow-moving line of intermediate cans, the open intermediate cans will more smoothly approach and join an upstream line of intermediate cans.

It may be preferred that the feed screw arrangement comprises two feed screw members arranged in parallel along each side of the flow of intermediate cans such that each intermediate can is transported between the two feed screw members that are arranged to operate in cooperation with each other. This provides for a secure feeding grip of the intermediate cans and reduces the risk that an intermediate can slips past its space in the feeding screw.

The main conveyor member may comprise slide guides and carrier bars, the slide guides being configured to support the intermediate cans when transferred to the main conveyor member and to allow them to slide in the transport direction and the carrier bars being distributed at defined distances along a moving and conveying part of the main conveyor member such as to push the containers along the slide guides. In this way, the intermediate cans are prevented from sliding in relation to a regular moving part, such as a conveying band, which would result in randomly varying distances between adjacent intermediate cans, causing problems in the subsequent gripping step. The use of slide guides and carrier bars as set out herein further improves positioning of the intermediate cans prior to gripping as the distance between adjacent transferred intermediate cans delivered to the gripping arrangement is predefined and non-varying.

The transporting means may further comprise an inlet conveyor member configured to feed containers to the feeding arrangement. The inlet conveyor member may be configured to operate at a transport speed that approximately corresponds to, and is uniform in relation to, an initial feeding speed at an inlet side of the feeding arrangement. This provides for a smooth transition for the intermediate cans between the inlet conveyor member and the feeding arrangement. Preferably, the inlet conveyor member also forms a support for the intermediate cans while being fed along the feeding arrangement. The inlet conveyor member may be configured to allow the intermediate cans to slide while supported when their feeding speed increases during feeding along the feeding arrangement. The inlet conveyor member may comprise an endless steel band that transports and supports the intermediate cans.

The attachment unit may comprise at least two subunits, each subunit comprising a cavity adapted to receive at least an end part of the intermediate can where the can component, such a top sealing member, a bottom sealing member or a rim is to be fastened, wherein an inductive welding energy generator, such as a coil, extends around the cavity such as to circumferentially surround an intermediate can placed in the cavity along a distance corresponding to a peripheral edge of a can component placed in its intended fastening position in the intermediate can, each unit further comprising a can component positioning device configured to position a can component in the intended fastening position.

The positioning device may take the form of a press plunger which positions the can component inside the tubular body of the intermediate can and thereafter expands radially to exert a radially outwardly directed press force on the inserted can component and to cause a portion of the can component to be pressed against the inner surface of the tubular body. The can component is held under pressure against the inner surface of the tubular body while welding the can component to the tubular body.

The positioning device may comprise two parts which are axially movable in relation to each other:

-   -   a base plate comprising or consisting of a rigid material, and     -   a resiliently deformable plunger skirt.

Axial movement between the two parts of the positioning device may be accomplished by means of a first piston and a second piston, the first and second pistons extending in an axial direction with the second piston being coaxial with the first piston. The base plate is connected to an end portion of the first piston, such that the footprint surface of the base plate is perpendicular to the axial direction. The plunger skirt is connected to an end portion of the second piston. The first piston and second piston are configured to be axially displaceable in synchrony with each other as well as independently of each other. The end portion of the second piston is configured to be closer to the end portion of the first piston when the plunger skirt is in an expanded state as compared to an unexpanded state.

When inserting the can component to the attachment position in the tubular body, the first piston and the second piston are axially displaced in synchrony with each other, moving together as a single unit. When transforming the plunger skirt to the expanded state, the first piston and the second piston are displaced independently of each other, such that the second piston is displaced in relation to the first piston in the axial direction. Thereby, the plunger skirt is pressed down on the base plate and is flattened out such that the outer circumference of the plunger skirt is caused to assume the expanded state. The elastically deformable plunger skirt will automatically return to the unexpanded state once the pressure exerted on it from the first and second pistons is ceased after application of the container element at the desired location inside the container body.

The base plate has a footprint surface with a circumferential edge, which circumferential edge comprises a plurality of side edge portions connected by corner portions. The plunger skirt covers a surface of the base plate opposite the footprint surface.

As set out herein, the plunger skirt is transformable between the unexpanded state and the expanded state. The plunger skirt has an outer circumference, which in the unexpanded state is located at the circumferential edge of the footprint surface of the base plate, and which in the expanded state is located at least partly outside of the circumferential edge of the footprint surface of the base plate.

The outer circumference of the plunger skirt in the unexpanded state preferably has a shape corresponding to a shape of the circumferential edge of the footprint surface.

At least one of the side edge portions of the circumferential edge of the base plate may comprise a curved segment, which is curved in an inward direction from the circumferential edge of the footprint surface, and at least one corresponding side portion of the outer circumference of the plunger skirt may comprise a curved segment, which is curved in an inward direction from the outer circumference of the plunger skirt.

The plunger skirt is arranged on top of the base plate, covering an upper surface of the base plate which is opposite the footprint surface. When the plunger skirt is in the unexpanded state, it will not be in contact with the can component or will at least not exert any force on the can component, during insertion of the can component to the attachment position inside the tubular body. When the can component has reached the attachment position, the plunger skirt is caused to expand in a radial direction thereby pressing an edge portion of the can component circumferentially against the inner surface of the tubular body. In this expanded state of the plunger skirt, a cross-sectional area delimited by the outer circumference of the plunger skirt is larger than in the unexpanded state of the plunger skirt.

By the provision of at least one curved segment of the circumferential edge of the footprint surface of the base plate and a corresponding at least one curved segment of the outer circumference of the plunger skirt, the risk of the positioning unit impacting on the upper edge of the tubular body and thereby damaging the tubular wall of the tubular body when inserting the can component may be considerably reduced, or eliminated.

During transformation to the expanded state, the plunger skirt will be flattened out and any inwardly curved segment or segments will at the same time straighten out, at least to a degree where the outer circumference of the plunger skirt extends beyond the circumferential edge of the footprint surface. Hence, by carefully selecting the shape of the plunger skirt in the unexpanded state and/or the material properties, a desired change of shape during transformation may be obtained. The material used for the plunger skirt, may be any useful elastically deformable wear and heat resistant material as known in the art, such as natural or synthetic rubber materials, e.g. polyamides, polyurethanes, polyesters, etc.

The method as disclosed herein may be at least partly carried out using an apparatus having components as set out above and may include the steps of:

-   -   transferring intermediate cans one by one in a continuous manner         from a feeding arrangement to a main conveyor member,     -   transferring intermediate cans from the main conveyor member to         an attachment unit by means of a movable gripping arrangement,     -   separating adjacent containers from each other in the direction         of transport by increasing the feeding speed of each individual         intermediate can along the feeding arrangement and thereby         increasing the distance between adjacent intermediate cans fed         along the feeding arrangement,     -   operating the main conveyor member at a transport speed that         approximately corresponds to, and is uniform in relation to, a         discharge speed of the intermediate cans when fed out from the         feeding arrangement such that intermediate cans transferred to         and along the main conveyor member remain separated,     -   gripping, by means of the movable gripping arrangement, at least         two intermediate cans and transferring these intermediate cans         simultaneously from the main conveyor member to the attachment         unit, and     -   fastening simultaneously a can component to each of the         simultaneously transferred intermediate cans.

The moveable gripping arrangement may comprise a first and a second gripping element arranged to operate on opposite sides of the flow of intermediate cans, wherein the gripping elements are movable towards and away from each other for gripping and releasing the intermediate cans, respectively, and wherein the gripping elements, in a synchronized manner, are movable along the flow of intermediate cans between the main conveyor member and the welding unit for the simultaneous transfer of two or more intermediate cans, each gripping element being provided with at least two recesses, such as four recesses, for gripping on each side of a corresponding number of simultaneously gripped intermediate cans, wherein the distance between the recesses of the gripping elements corresponds to the distance between intermediate cans positioned on the main conveyor member during operation of the apparatus.

The movable gripping arrangement may be configured to grip four containers and transfer these four intermediate cans simultaneously from the main conveyor member to the welding unit, wherein the welding unit is configured to simultaneously fasten a can component to each of the four intermediate cans.

The feeding arrangement may comprise a second movable gripping arrangement and an outlet conveyor member arranged downstream of the attachment unit, wherein the second movable gripping arrangement is configured to grip the at least two intermediate cans and transfer these intermediate cans simultaneously from the attachment unit to the outlet conveyor member.

A sliding guide, such as a stationary sliding plate may be arranged at the end of the outlet conveyor member such that the intermediate cans may slide on the sliding plate from the outlet conveyor member to a further conveyor member for transporting the intermediate cans to a subsequent machine unit in the production line. Such a sliding plate decreases the feeding speed of the intermediate cans and reduces the distance between them. Thus, the intermediate cans are again lined up close to each other in a continuous row in the same way as at the upstream side of the feeding arrangement.

As set out herein, the attachment unit may be arranged in an external housing and a protective gas atmosphere may be created inside the external housing. An outlet port for the intermediate cans may be arranged in the external housing, wherein the size of the opening is adapted to the size of the intermediate cans being processed. The outlet port may comprise a short tunnel arranged at the end of the outlet conveyor member, wherein the sliding plate constitutes a floor in the tunnel. The outlet conveyor pushes the intermediate cans onto the stationary sliding plate, thereby creating a continuous row of intermediate cans which pass through the outlet tunnel. As the size of the outlet tunnel is adapted to the size of the intermediate cans, the cans fill out the cross section of the outlet tunnel, whereby the outlet port becomes relatively gas-tight during operation of the device without any need for additional equipment. The provision of the stationary sliding plate in the outlet tunnel, ascertains that there will always be an intermediate can in the outlet tunnel acting as a “plug” and preventing protective gas from escaping and air entering through the outlet from the external housing. In a corresponding manner, the size and shape of an inlet port with an inlet tunnel into the external housing may be adapted to the size and shape of the intermediate cans produced on the assembly line as disclosed herein. However, as the inlet conveyor may already be arranged in a protective gas atmosphere, it is generally sufficient to arrange a closable hatch at the inlet to the attachment unit, in order to allow the inlet port to be closed off, as needed.

When transporting intermediate cans which have been filled but not yet sealed, it is desired to maintain a protective gas atmosphere intact from its creation up until the bottom of the intermediate can has been closed over the filled contents. A protective gas atmosphere may be created already during the filling stage, e.g. by blowing protective gas into the flow of material before the material reaches the can. Alternatively, filled intermediate cans may be introduced into a vacuum chamber to draw off air, whereafter the cans are subjected to a modified gas atmosphere and the bottom sealing member is applied.

In all instances, the filled cans are transported to the sealing unit in a closed conveying system while maintaining the protective gas atmosphere. In order to ascertain that no protective gas escapes at the interfaces between the conveying system and the can sealing unit, tightly fitted lead-in and outlet tunnels may be arranged at the inlet and outlet of the sealing unit, as disclosed herein.

The method as disclosed herein may include application of a scoop in the compartment formed between the top sealing member and the reclosable lid. The scoop is preferably applied to the intermediate can after filling and before attaching the reclosable lid at the top end of the tubular body. The scoop may be applied directly on the top sealing member or may be placed in a scoop holder which is arranged above the top sealing member. A scoop holder may be formed as an integral part of the top rim or may be an added-on part of the top rim. A scoop holder which is arranged on the top rim may include a scraper bar for scraping off excess scooped-up contents from the scoop head. The scoop head and the scoop holder may have matched shapes such that the scoop may be placed with the scoop head securely fitted in the scoop holder with the scoop handle held above the top sealing member in a generally horizontal position. The scoop head and scoop holder may be arranged such that the scoop head may snap into engagement with the scoop holder, e.g. by the scoop head being provided with one or more protruding elements such as one or more knobs or ridges, which snap under an edge of the scoop holder when the scoop head is pressed into the scoop holder. A snap-in engagement between the scoop head and the scoop holder ascertains that the scoop remains securely held in a predetermined position in the scoop holder, without rattling and without the scoop handle dipping down into the contents of the composite can once the top sealing member has been removed by a user.

The reclosable lid may have a scoop holder in the form of a clamp arranged on the inner surface of the reclosable lid. A scoop holder on the inner surface of the reclosable lid may be provided as an alternative or in addition to a scoop holder on the top rim.

The scoop may be placed in the can as it is or may be prepacked in a hygienic wrap, such as in a plastic bag.

The barrier properties of the cans as disclosed herein, may be designed to meet different requirements of tightness depending on the goods which is packaged in the can. By way of example, in a can for dried peas a lower barrier level may be acceptable than in a can for e.g. infant formula which is highly sensitive to oxygen and moisture exposure. A combination of a gas-tight gasketing seal between an upper edge of the top rim and the inner surface of the reclosable lid, and a gas-tight weld seal between the top rim and the inner surface of the tubular body may offer a can with excellent barrier properties also after the top sealing member has been removed.

The cans produced by the method as disclosed herein may preferably have barrier properties which remain largely unaltered even after breaking or removal of the top sealing member. In other words, the contents in a closed can may be equally well protected or nearly equally well protected regardless of whether the top sealing member has been opened or not. This also means that the seal created between the reclosable lid and the top rim as well as the weld seal between the top rim and the inner surface of the can preferably have barrier properties offering the same level of protection of the packaged contents as an unbroken top sealing member.

As set out herein, a welding process, in particular a high frequency induction welding process, provides a highly controlled way of creating a join with a predetermined level of tightness between the top rim and a thermoplastic layer of the carton based material in the tubular body. The join is made by supplying energy to heat and locally soften or melt one or more thermoplastic component in the plastic rim and/or on the inner surface of the tubular body and by pressing the plastic rim and the tubular body together in a direction perpendicular to the inner surface of the tubular body. The thermoplastic material used to create the weld seal may be provided by the plastic rim, by a thermoplastic film or coating on the inner surface of the tubular body, or by both the plastic rim and by a thermoplastic film or coating on the inner surface of the tubular body. It may be preferred that the plastic rim is made from thermoplastic material. A thermoplastic rim may be produced by any suitable melt-forming process known in the art, such as injection molding. By controlling the supplied amount of energy, the applied pressure, and the weld time, it is possible to adapt the welding process to the welded materials and to obtain a weld seam with a required level of tightness. Accordingly, the welding process is accurate and predictable and is an efficient way of producing a reliable seal with a predetermined level of tightness.

After filling of the can with the packaged product, the bottom end is closed to seal the product in an inner compartment of the can. Closing of the bottom end is performed by attaching the bottom sealing member to the inner surface of the tubular body, as set out herein. The bottom sealing member is preferably attached at a small inward distance from the bottom end edge of the tubular body to provide stackability and/or to facilitate application of a bottom rim at the bottom end of the tubular body. Insertion of the bottom sealing member may give rise to a slightly higher than ambient pressure inside the sealed intermediate can. This overpressure has been found to cause a slight outward bulge in the top sealing member. In a two layer top sealing member having a partially cut-out tear strip in an upper outer layer of the sealing member, the slight outward bulge in the top sealing member has been found to promote raising of a grip end of the tear strip from the underlying layer. In this manner, the grip end is easier to grasp, whereby pulling away of the top sealing member is facilitated.

The bottom sealing member may be made from any suitable material such as carton, plastic, metal and laminates of such materials, with carton based bottom sealing members being generally preferred. A carton based bottom sealing member may be made from a laminate material comprising a carton layer, a metallic foil layer and a thermoplastic polymeric layer being arranged at an inner surface of the carton layer facing towards an interior of the container body, with the metallic foil layer being arranged between the carton layer and the thermoplastic polymeric layer. A further thermoplastic polymeric layer may be arranged at an outer surface of the carton layer. The bottom sealing member may be attached by welding, such as by high frequency induction welding, to the inner surface of the tubular body. The bottom sealing member is shaped before or during insertion into the bottom opening by bending a peripheral edge portion out of the plane of the bottom sealing member to create a flange which is aligned with the inner surface of the tubular body and which can be welded to the inner surface of the tubular body. The weld seal between the bottom sealing member and the container body wall is much less sensitive to contamination by the packaged material than is the weld seal between the top sealing member and the inner surface of the tubular body. A carton based bottom sealing member is generally thicker and more compressible than the top sealing member and it is easier to form a tight seal between the bottom sealing member and the tubular body. The amount of packaged material which may escape out of the intermediate can when the bottom sealing member is inserted into the bottom opening is very small. As the bottom sealing member is only inserted a very small distance into the tubular body, the insertion step generates only a minimum of turbulence at the surface of the packaged material. The amount of material which is lost in the closure step is thereby minimal. Any material which ends up on the outside of the bottom sealing member after the intermediate can has been closed and sealed can be easily removed and will not cause the fully assembled composite can to look soiled.

Alternatively, the bottom end of the composite can may be closed by any suitable method as known in the art such as by folding and sealing end portions of the container wall.

After sealing the bottom, and optionally attaching a bottom rim to the bottom end of the composite can, the composite can may be conveyed in a conventional manner to equipment such as a code marking unit, a weighing unit, a leaflet inserter, a scoop inserter, etc.

The lid application step of the method as disclosed herein may further comprise applying a frame structure by mechanically attaching the frame structure to the top rim. A mechanical connection between the top rim and the frame structure may be accomplished by the provision of mating contours on the top rim and on the frame structure. Such mating contours preferably include snap-fit features such as interengaging ridges and tracks or protrusions and holes/cavities, etc.

A frame structure may be configured to cooperate with a plug-in lid or a hinge-lid to keep the lid in a closed position with an inner surface of the lid in direct contact with an upper surface of the top rim. The frame structure may be applied together with the lid.

The attachment between the frame structure and the top rim may be made by forming a snap-in connection between the frame structure and the top rim.

The mechanical connection between the top rim and the frame structure is preferably irreversible implying that once established the connection can only be broken by destroying or damaging the connected parts.

The frame structure may form part of a lid component, the lid component further comprising a lid part which is connected to the frame structure by a hinge. The lid part may be a complete lid or may be only part of a lid, which is assembled with one or more additional lid parts to form a container lid. By way of example, the lid part may be an outer lid part defining the shape and size of the portion of the lid which is exposed to the exterior of the composite can and which is combined in the container lid with an inner lid part such as an inner sealing member which provides an abutment surface cooperating with a corresponding abutment surface on the top rim to form a gasketing seal between the lid and the top rim. The inner sealing member may take the form of a planar disc and may be made from carton, plastic, or any suitable laminate and may include resiliently compressible material such as natural or synthetic foam materials or other resiliently compressible polymer materials which may contribute to a tight seal between the lid and the top rim. The inner sealing member may be attached to an outer lid part by adhesive or welding. However, it may be preferred that the inner sealing member is mechanically attached to the outer lid part, such as by being snapped into a groove extending along the edge of the outer lid part, on an inner surface thereof.

It may further be advantageous to attach the inner sealing member to the outer lid part under tension as a tensioned inner lid part has been found to have enhanced sealing capability.

When the lid part constitutes a complete lid, it is the inner surface of the lid which forms the seal against the abutment surface of the top rim. The inner surface of the lid may be coated with a resiliently compressible material at least within the area corresponding to the abutment surface of the top rim or may comprise a layer of a resilient material on the inner surface of the lid.

By providing a lid, a frame structure or a lid component as parts which are separate from the top rim, these parts may be attached to the top rim after the intermediate can has been filled and the bottom end has been closed. A lid, frame structure, or lid component may have a three-dimensional profiled shape, with stacking features, decorative relief elements, locking elements, and other aberrations and irregularities. Furthermore, a lid or lid part may have a non-planar surface, such as a rounded surface or an irregularly shaped surface. All such three-dimensional features make an intermediate composite can difficult to handle in a bottom filling process as the intermediate can may not be safely rested on the non-planar upper surface formed by the lid or lid component. Plastic components having a complicated three-dimensional shape are comparatively expensive to manufacture, and can easily be damaged in a process when transferring the intermediate can between different process stations, gripping and repositioning the can, attaching can components, filling and closing the can. By applying the frame structure or lid component after filling and closing the can, the number of cans which are damaged in the process and which have to be discarded can be lowered. An upper closure comprising a lid and a two-part rim/frame construction as disclosed herein may serve to keep waste at a lower level than is possible with a conventional single part rim constructions. The top rim as disclosed herein has a simple shape without protruding features that may be damaged in a production process and may serve as a support and reinforcement element for the tubular body during the manufacturing and filling process as set out herein. In the assembled composite can, the top rim contributes to stabilise and shape the carton based body during transport and storage.

The reclosable lid may be applied to the upper end of the intermediate can after the inner packaging compartment in the tubular body has been filled with the packaged product and the bottom end of the tubular body has been closed.

The reclosable lid may be a separate part of the composite can which can be completely removed when opening the can. Alternatively, the lid may be attached to a frame structure by means of a hinge, as set out herein. The hinge may be a live hinge, i.e. a bendable connection between the lid and the frame structure. A live hinge may be formed integral with the lid and/or with the frame structure or may be a separately formed element which is attached to the lid and to the frame structure. Alternatively, the hinge may be a two-part hinge, with a first hinge part arranged on the lid and a second hinge part arranged on the frame structure. A two-part hinge construction may alternatively be used to attach the lid directly to the top rim

If the reclosable lid comprises an outer part and an inner sealing disc, the inner sealing disc is preferably attached to the outer part of the reclosable lid part before attaching the reclosable lid or lid component to the intermediate can. Although less preferred, the inner sealing disc may alternatively be attached to the outer part of the reclosable lid after attaching the reclosable lid or lid component to the intermediate can.

In a composite can produced according to the method as disclosed herein, an inner profile of the top rim defines a shape and a size of an access opening, whereby the access opening is smaller than the top opening of the tubular body. The opening area of the access opening is preferably from 85% to 99% of the area of the top opening of the tubular body, such as from 90% to 98% of the area of the top opening of the tubular body or from 94% to 97% of the area of the top opening of the tubular body. The top rim preferably builds as little as possible into the can opening, such that the size of the access opening is maximized. A slim top rim and a large access opening make the contents in the can easily accessible and contribute to facilitate scooping or pouring of the contents out of the can. A slim inner top rim minimizes the risk that particulate material is caught on surfaces of the rim during scooping or pouring of contents from the can or when a closed can is moved or shifted between dispensing occasions. A user opening the can and revealing a soiled top rim, will perceive the can as being messy and less hygienic than desired. It is generally desired to keep the packaged product away from the access opening where it is more exposed to contamination as it may more easily come into contact with the hands of a person opening the can and removing contents through the access opening. Contaminated contents in the can which are caught on the top rim may fall back into the can and may, in turn, contaminate the remaining contents in the can.

If the packaging can is provided with a frame structure which is mechanically connected with the top rim, it may be preferred that no part of the frame structure extends into the access opening and detracts from the area of the access opening. The frame structure may then serve to provide features such as a lid hinge, means for retaining the lid in a closed position over the access opening, locking elements, stacking elements, etc.

The top rim or a frame structure may further be configured with means for retaining the lid in a closed position with an inner surface of the lid in direct contact with an upper edge of the top rim. Such means may be constituted by snap-lock elements including mating ridges and grooves on the rim or frame structure and on the lid, female/male locking elements, etc. as known in the art. In addition thereto, the closure arrangement on the composite can preferably comprises a locking arrangement.

The locking arrangement may comprise a first locking element arranged on a frame structure if present, on the tubular body or the composite can or on the top rim, and a second locking element arranged on the can lid. The first and second locking elements may be mating locking elements, such as female/male locking elements including hooks and other protrusions which are arranged to interengage with ridges, hooks, tracks, holes, cavities, loops, etc.

The locking arrangement may comprise at least one locking flap being permanently joined to the top rim or to a frame structure, such as at a front edge portion and/or at a side edge portion of the access opening of the can. The locking flap has a free end portion extending towards the reclosable lid in a height direction of the composite can. The free end portion of the locking flap comprises a first locking element which is arranged to mate with a second locking element on the outer surface of the reclosable lid. Preferably, the locking flap has an extension in the height direction of the composite can which allows the free end portion to reach a distance in over a top portion of the outer lid surface such that the first and second locking elements may be arranged to mate on the top portion of the outer lid surface at the edge of the reclosable lid. When the locking flap is in the closed position with the first and second locking elements engaging with each other, the lid and the top rim or frame structure are firmly clamped together and kept under tension. The locking flap is preferably hingedly connected to the top rim or the frame structure, preferably by means of a live hinge formed integrally with the top rim or frame structure and the locking flap.

An inset gripping area may be arranged in the outer lid surface of the top portion of the lid part. The inset gripping area is arranged at the free end portion of the locking flap and serves to provide access to the free end portion of the locking flap in a direction perpendicular to the height direction of the lid component. Thereby, the locking flap can be easily manipulated even if no part of the locking flap in the closed position extends in the height direction of the lid component beyond the outer lid surface of the top portion of the of the lid part.

Alternatively, although generally less preferred, a locking arrangement may be provided by a locking flap or clasp closure extending from an edge on the lid, such as from a forward edge on the lid and comprising at least one locking element which can be fastened into or onto a corresponding locking element on the top rim or on a frame structure.

The locking elements are preferably designed to allow repeated opening and closing of the locking arrangement. Manipulation of the locking arrangement may be facilitated by means of gripping devices such as finger grips, friction enhancing elements, pull tabs, etc.

A stacking member or stacking members at the can opening may be arranged peripherally on the lid and/or on a frame structure connected to the top rim surrounding the access opening in the packaging can. The lid may be provided with mating stacking members arranged on the upper outer surface and on the inner lower surface of each lid, making the lids separately stackable before being applied to an intermediate can, e.g. in a process for producing the packaging cans as disclosed herein. In a similar fashion, lid components comprising a lid part hingedly connected to a frame structure may be provided with mating stacking members making the lid components separately stackable.

A stacking member at the can opening may take the form of a peripheral ledge on the outer lid surface or on the top rim or on a frame structure connected to the top rim. When one can is stacked on top of another can, a bottom edge or bottom rim of the first can is supported on the peripheral ledge.

A lid component for a composite can as disclosed herein has a lateral direction and a height direction perpendicular to the lateral direction and comprises a lid part and a frame structure, the lid part comprising a top portion and a side wall portion. The top portion has an outer lid surface and an inner lid surface opposite to the outer lid surface and a peripheral edge surrounding the outer lid surface. The frame structure comprises an upper portion and a lower portion in the height direction and has a lower edge surface. Stacking members may be arranged on the outer lid surface, the stacking members on the outer lid surface comprising a lid component stacking step and a can stacking step. The can stacking step comprises a first support surface arranged at a first level below an uppermost level of the outer lid surface in the height direction of the lid component and the lid component stacking step comprises a first support surface arranged at a second level below the uppermost level of the outer lid surface and below the first level in the height direction of the lid component. The lid component stacking step is arranged at the peripheral edge of the outer lid surface, outboard of the can stacking step in the lateral direction of the lid component, and the frame structure is adapted to fit on and be supported by the lid component stacking step. The can stacking step is adapted for receiving and supporting a bottom edge of a composite can.

The lid part and the frame structure of a lid component as disclosed herein may be fully separable parts, partially separable parts or completely inseparable parts. In a lid component having fully separable parts, the parts are separably and reclosably connected to each other in a closed configuration of the lid component. In a lid component having partially separable parts, the parts are connected to each other by a hinge and can be moved between a closed configuration of the lid component and an open configuration of the lid component by pivoting around the hinge. A lid component having inseparable parts is a lid component in which the frame structure forms an integral continuation of the side wall portion of the lid part.

As set out herein, a bottom rim may be attached to the tubular body of the composite can at the bottom end of the tubular body. In a composite can which is provided with stacking steps on the reclosable lid or on a lid component comprising the reclosable lid, the bottom rim is adapted for stacking cooperation with a can stacking step on the top portion of the lid or lid part.

In a composite can as disclosed herein, a lower end surface of the bottom rim may be adapted for stacking cooperation with the first support surface of the can stacking step and an inner wall of the bottom rim may be adapted for stacking cooperation with the second support surface of the can stacking step. When stacking a second can as disclosed herein upon a first can as disclosed herein, the lower end surface of the bottom rim of the second can rests on the first support surface of the can stacking step of the first can and the second support surface of the can stacking step restricts lateral movement of the second can in relation to the first can.

As set out herein the stacking members are arranged on the outer lid surface of the lid component and comprise a lid component stacking step and a container stacking step with the lid component stacking step being arranged laterally outboard and below the can stacking step. By arranging the stacking members at the very edge of the lid part, the stacking members intrude minimally on the top surface of the lid and a large central area of the lid is left available for display purposes, e.g. for conveying information, logos, and/or for design purposes. As the stacking steps are arranged at levels below the central area of the top surface of the lid part, they are inconspicuous and the technical character of their function as stacking members may not be immediately apparent to an end user of the composite can. The composite can may be perceived as having a more appealing and “designed” appearance and less of a technical character which may be beneficial when the can is placed where it can be seen such as on a counter top in the user's home or on a shelf in a shop.

When stacked together, the lid components provided with stacking steps as disclosed herein are nested in each other such that they may be stacked in a space saving yet efficient and stable manner with each lid component adding less to the height of the stack than a height of the lid component. Thus, a combined height of the stacked lid components is less than the sum of the individual heights of the lid components. A space saving stacking configuration is advantageous for transport and storage purposes as well as during production of composite cans. A space saving stacking renders the supply of lid components in the production process more efficient as magazines for lid components may contain a greater number of lid components and require less frequent refilling.

Accordingly, the two-step configuration of the peripheral portion of the lid part of the lid component offers stable and efficient stacking of individual lid components as well as of composite cans comprising the lid components. The provision of separate stacking steps for the lid components and for the composite cans on the outer surface of the lid part of the lid component makes it possible to size and configure each stacking step to be optimal for the particular stacking purpose.

The lid part of the lid component is provided with two different and distinct stacking members arranged as two generally L-shaped stacking steps at the peripheral edge of the outer lid surface. The lid component stacking step is located outward of the can stacking step as seen in the lateral direction of the lid component and below the can stacking step as seen in the height direction. When stacking a second lid component on a first lid component, the lid component stacking step of the first lid component receives the lower portion of the frame structure of the second lid component in a mating fashion such that the lower portion of the frame structure fits in a nesting manner on the lid component stacking step.

The lid component stacking step and the can stacking step may each comprise a second support surface.

The second support surface of the lid component stacking step may be arranged to support an inner wall of the lower portion of the frame structure, i.e. to support the second lid component in the lateral direction of the lid components. Accordingly, first and second support surfaces may be arranged to take up forces in two generally perpendicular directions corresponding to the vertical direction and the horizontal direction when the lid components are stacked on each other on a horizontal surface.

The lid component stacking step and/or the can stacking step may comprise one or more interruptions, such as two interruptions, three interruptions or four interruptions. The interruptions may be arranged as a pair of interruptions at opposite locations along the peripheral edge of the outer lid surface, e.g. at opposite side portions of the peripheral edge of the outer lid surface. The interruptions may be arranged only in the top portion of the lid part or may be arranged also in the frame structure of the lid component.

Interruptions in one or both stacking steps may serve as separation means for facilitating gripping and separation of individual lid components from a stack of lid components when applying the lid components to an intermediate can in a production process for producing a composite can as disclosed herein. The provision of separation means is particularly useful when stacking lid components which fit snugly on each other with very thin split lines between the stacked lid components. Although such close-fitting lid components form compact stacks with a smooth and regular shape, which is beneficial for storage and transport of the stacked lid components as well as for handling of the stacks of lid components in a packaging machine, it has been found that the lid components tend to stick closely together and to be difficult to separate at the high speed required in a production process. In addition to facilitating separation of the closely stacked lid components by inserting gripping members into the interruptions, the interruptions counteract the formation of a sub-atmospheric pressure in the spaces between the stacked lid components as the interruptions act as air channels between the interior of the stack and the exterior of the stack. A lowered air pressure in the interior spaces between the stacked lid components creates a suction force which tends to hold the lid components firmly together. Conversely, a higher pressure in the interior of the stacks than on their outside may tend to decrease the stability of the stacks by forcing the lid components apart.

The stacking steps may extend over a locking flap arranged at the edge of the lid, whereby the locking flap in the closed position forms a continuation of the side wall portion of the lid part. At the same time, the parts of the stacking steps which are arranged on the locking flap may contribute to improve grippability of the locking flap and facilitate manipulation of the locking flap between the open and closed positions.

An inset gripping area may be arranged in the outer lid surface of the top portion of the lid part. The inset gripping area is arranged at the free end portion of the locking flap and serves to protect the free end portion of the locking flap from inadvertent opening and while providing access to the free end portion of the locking flap. Thereby, the locking flap can be easily manipulated even if no part of the locking flap in the closed position extends in the height direction of the lid component beyond the outer lid surface of the top portion of the of the lid part.

As an alternative to a continuous or discontinuous ledge or stacking steps which are arranged at the periphery of the outer lid surface, stacking members at the can opening may be provided as two or more support surfaces cooperating with corresponding stacking members at the bottom of the can. The stacking members at the bottom of the can may be in the form of a downwardly extending bottom edge as set out above or may be in the form of knobs or other protrusions providing a desired spacing between a can bottom sealing member and the peripheral ledge or other support surface on which the stacking member or members at the bottom of the can are resting when one can is stacked on top of another.

The tubular body of the composite can as disclosed herein may have four main body wall portions; a front wall portion arranged opposite a rear wall portion and two opposing side wall portions extending between the front wall portion and the rear wall portion. The body wall portions are connected by curved corner portions providing the packaging can with a soft, slightly rounded appearance. Moreover, the shape of the body wall portions may deviate from a planar shape, with one or more of the body wall portions having an outward or inward curvature. When the tubular body has one or more outwardly curved body wall portion the curvature of any such body wall portion is always lesser than the curvature of any curved corner portion, i.e. a radius of curvature of a corner portion in the tubular body of the composite can as disclosed herein is always smaller than any radius of curvature of a body wall portion. A transition between a corner portion and a body wall portion may be seen as a distinct change in curvature or may be seen as a continuous change in curvature.

Alternatively, the tubular body can be made without distinct body wall portions and may have any suitable foot-print shape, such as circular, oval or elliptic.

In composite cans, there is a conflict between minimizing the amount of carton material used in the cans and making the cans sufficiently rigid to avoid that the cans are damaged or that they collapse, e.g. during production of when stacked for transport and storage. It has been found that by making all can walls only slightly outwardly curved, shape stability and rigidity of the composite can may be considerably improved as compared to conventional packaging cans having planar walls. Accordingly, the radii of curvature of the top and bottom end edges of the tubular body which govern the curvature of the can wall portions are preferably selected such that the can wall portions are provided with a near-planar shape, implying that the can wall portions are perceived by the naked eye as being planar.

The carton based composite cans as disclosed herein serve as protective transport and storage cans at the retail end and as storage and dispensing cans at the consumer end. In addition to an openable and closable lid the composite cans are manufactured with a top sealing member which is attached inside the tubular body of the can, at a distance from a top end edge of the tubular body. The top sealing member keeps the contents fresh and protected against contamination up until delivery of the filled and sealed can to a consumer. Once the top sealing member has been broken or removed in order to access the contents in the can, the ability of the can to protect the contents from detrimental influence from the environment depends strongly on the ability of the reclosable lid to form a tight closure at the access opening of the can. A composite can for products such as baby formula, coffee, tea, cereals, etc., usually contains more of the packaged product than will be used at each dispensing occasion. Thus, it is desirable that the product remaining in the can retains properties such as flavor, scent, scoopability, vitamin content, color, etc. at least for a time period corresponding to the time it is expected it will take for a consumer to use up all the contents in the packaging can.

As set out herein, by joining the top rim to the inner surface of the tubular body by means of welding, such as high frequency induction welding, it is possible to obtain an attachment with better sealing ability than what is generally achievable with an adhesive attachment. The welded top rim is preferably a plastic rim and connects the inner surface of the tubular body with the inner surface of the lid and contributes to create a continuous barrier between the tubular body and the lid. The weld seal forms a first seal between the top rim and the inner surface of the tubular body and the contacting surfaces of the top rim and the lid form a second seal between the top rim and the lid. The first seal is a permanent seal which is present at all times and the second seal is an openable seal which is effective only when the lid is closed on the can access opening and the inner surface of the lid is pressed against the top rim.

The lid or a lid component may be applied using a lid attachment unit which is an apparatus for automatic application of lids to intermediate cans. The lid attachment unit may comprise a rotatable unit comprising lid holding members, a lid feeding unit and a lid application unit. The apparatus may further comprise an item application unit configured to apply an individual additional item into the intermediate can, into a holder arranged on the top rim or on the inside of the lid. The additional item may be a scoop or other implement, a toy, a brochure, etc. Alternatively, an item applicator may be provided as an apparatus separate from the lid attachment unit.

After application of a lid, e.g. in the form of a lid component, the assembled composite can may be conveyed in a conventional manner to further equipment in a packing line, such as a box packer, a code marker, a weighing unit, and a palletizer. The packing line is usually concluded by a palletizer.

Definitions

The carton based sheet materials used for forming the tubular body and the base sealing member are predominantly made from cellulose fibres or paper fibres forming a carton layer in the paperboard material. The carton layer may be a single ply or multi ply material. The sheet materials are laminates which in addition to the carton layer comprise at least one thermoplastic polymeric layer in the form of a film or a coating and a metal foil layer, preferably an aluminum layer. The metal foil layer is covered by the at least one polymeric layer and is arranged at a surface of the sheet material which will form an inner surface of the composite can, i.e. at a surface which will be facing the interior of the composite can. A polymeric layer may also be arranged at a surface of the sheet material which will form an outer surface of the composite container. In addition to the inner layers of polymer and metal foil, and an optional outer polymer layer, the sheet material may be coated, printed, embossed, etc. and may comprise fillers, pigments, binders and other additives as known in the art.

The term “tubular body” should be understood to mean any hollow tubular shape the body blank assumes during manufacturing and filing of the composite cans as disclosed herein, as well as the shape the body has in the finally assembled and filled composite can. Accordingly, a tubular shape as used herein may be a cylindrical shape, or a shape with any other useful cross-section such as a square, rectangular or other polygonal cross section or modified polygonal cross sectional shapes with rounded corners. A tubular shape also includes any transient shape that the tubular body may assume during the manufacturing process. By way of example, the cross section of the tubular body may initially take on a drop-shape appearance with a distinct peak at the end-to-end join between the edges of the body blank and a curved portion opposite the peak.

The term “can component” as used herein refers to the tubular body of the composite can and any component which is intended to be attached to the tubular body in order to form an integral part of the composite can as disclosed herein. Examples of can components which may be part of a composite can as disclosed herein are: a tubular body, a body sealing strip, a top sealing member, a bottom sealing member, a top rim, a reclosable lid and a frame structure, a lid component, a bottom rim, a scoop holder, and a scoop. Only the tubular body, the body sealing strip, the top sealing member, the bottom sealing member, the top rim and the reclosable lid are mandatory components of a composite can as disclosed herein.

Top and bottom sealing members are sheet form components which are applied inside the tubular body of the composite can such that they cover a cross-sectional area of the tubular body. The bottom sealing member forms a bottom end closure of the composite can and the top sealing member forms an inner transport seal of the composite can. The top sealing member is usually attached at the access opening of the composite can, at a distance from the opening edge which is at least sufficient to allow for attachment of the top rim above the top sealing member and which may also allow for a scoop or other added item to be accommodated in the space between the top sealing member and the inner surface of the reclosable lid.

The top and bottom sealing members may be made from paper, carton, plastic film, aluminium foil and laminates of such materials. Usually, the bottom sealing member is made from a laminate comprising a carton base layer and an aluminium foil layer on the side which will be facing towards the interior of the composite can. The bottom sealing member is generally coated with outer layers of thermoplastic polymeric material. The top sealing member is commonly a flexible component made from a laminate of one or more layers of aluminium foil and outer layers of thermoplastic polymeric material. However, carton based top sealing members are also known in the art. The top sealing member is commonly arranged to be partly or fully removed at an initial opening of the composite can and may be provided with opening means such as a tear strip, a grip tab, etc. as known in the art.

Top and bottom rims are commonly made from plastic material, such as thermoformable plastic material and take the form of a closed loop, which is applied to the inner surface of the tubular body of the composite can with at least a portion of the rim welded to the inner surface of the tubular body. The plastic rims provide the tubular body with enhanced rigidity at the end edges of the tubular body. Preferably, the plastic rims are sufficiently resiliently deformable such that they may withstand sideways deformation without breaking or permanent deformation, e.g. when being inserted into the tubular body or when exposed to accidental impact during use. A rim may also cover an end edge of the tubular body and may optionally extend onto the outer surface of the tubular body.

An “intermediate can” as referred to herein is a can formed after bending a carton blank into a tubular shape and sealing joined edges of the bent carton blank to form a tubular body. The processed can remains an “intermediate can” until the last component has been applied to complete the composite can. In general, the composite can is fully assembled when the reclosable lid has been applied as a final component.

The composite cans as disclosed herein are cans for dry or moist goods, often referred to as “bulk solids”. Such products are non-liquid, generally particulate materials capable of being poured, scooped or taken by hand out of the cans. The cans are generally disposable cans, which are intended to be discarded when they have been emptied of their contents.

A “particulate material” or “particulate goods” should be broadly understood to include any material in the form of particles, granules, grinds, plant fragments, short fibres, flakes, seeds, pieces, etc. The particulate goods which are suitable for packaging in the composite cans as disclosed herein are generally flowable non-liquid goods, allowing a desired amount of the goods to be poured, scooped or taken by hand out of the composite can.

A composite can as disclosed herein may be a can for alimentary or consumable products such as infant formula, coffee, tea, rice, flour, sugar, rice, peas, beans, lentils, cereals, soup powder, custard powder, pasta, snacks, or the like. Alternatively, the packaged goods may be non-alimentary, such as tobacco, detergent, dishwasher powder, fertilizer, chemicals, or the like.

By an openable or peelable top sealing member is meant a sealing member that may be fully or partly removed by a user in order to provide initial access to an interior compartment of the composite can either by breaking a seal between the sealing member and the inner surface of the tubular body of the can, or by tearing or otherwise breaking the sealing member itself. Tearable sealing members may be provided with one or more predefined weakenings, such as perforations or a cut partly through the membrane and may have a tear strip arranged therein for facilitating removal of the sealing member. A peelable top sealing member is usually provided with a grip tab for facilitating initiation of the separation from the inner surface of the tubular body and subsequent removal of the sealing member.

The top sealing member is preferably placed at a distance from the upper end edge of the tubular body of the composite can which allows the top rim to be attached to the inner surface of the tubular body between the top sealing member and the top end edge of the tubular body. Alternatively, an upwardly directed edge part of a breakable sealing membrane may extend into the weld join between the top rim and the inner surface of the tubular body. The distance between the top sealing member and the top end edge of the tubular body may be in the order of from 10 to 60 millimeters. If the top sealing member is placed at a distance of from 30 to 60 millimeters from the top end edge of the tubular body, the space above the top sealing member may be used to accommodate a scoop or other item provided together with the packaged product. Examples of other items which may be provided are leaflets, coupons, and/or clips, forks, or other implements.

The weld seal between the top rim and the inner surface of the tubular body is preferably a sift-proof seal, more preferably a moisture-proof seal and most preferably a gas-tight seal. A can having a volume of approximately 11 may be considered to be gas-tight if it provides an oxygen barrier of approximately 0.006 cc oxygen/24 h or less at 23° C. and 50% relative humidity.

A higher level of tightness of the composite can and any seals between the elements of the can may be desirable when the packaged product is moisture sensitive and/or is sensitive to degradation when exposed to ambient air. It may also be desirable that the composite can is aroma-proof in order to preserve flavours and aromas in the packaged goods and to prevent the packaged product from taking up flavours and aromas from outside the composite can. Hence, the composite can may act as a barrier in both an inward and an outward direction.

By subjecting the filled goods in an open intermediate can to a protective gas atmosphere in conjunction with the filling step, the amount of air which is trapped inside the can when the bottom closure is applied can be minimized. Furthermore, as the protective gas atmosphere is created before the filled intermediate can reaches the sealing station, the atmosphere in the sealing station and the sealing step can be extremely well controlled as there is no need of removing air from the filled open containers before sealing the containers. This has been found to be a considerable advantage as pressure differences in the sealing step may negatively affect the sealing process by causing turbulence in the packaged material. Such turbulence may result in powdery material being captured in the seals and potentially compromising the tightness of the seals.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be further explained hereinafter by means of non-limiting examples and with reference to the appended drawings wherein:

FIG. 1 shows a schematic view of an assembly line for producing and filling a composite can;

FIG. 2a shows an exploded view of a composite can as disclosed herein;

FIG. 2b shows a scoop and a stack of scoops;

FIG. 3 shows the composite can in FIG. 2a with all components assembled;

FIG. 4 shows a can component applicator;

FIG. 5 shows an attachment unit which may be part of a can component applicator as shown in FIG. 4 in a first production stage;

FIG. 6 shows the attachment unit in FIG. 5 in a second production stage;

FIG. 7 shows a transport plate with transfer cavities; and

FIG. 8 shows a positioning device.

DETAILED DESCRIPTION

The invention will, in the following, be exemplified by embodiments. The embodiments are included in order to explain principles of the invention and not to limit the scope of the invention, as defined by the appended claims. Details from two or more of the embodiments may be combined with each other.

FIG. 1 illustrates an assembly line 1 which may be used for producing and filling composite cans according to the method as disclosed herein. The assembly line 1 is configured for assembling composite cans by forming a tubular body and attaching can components to the tubular bodies in a flow of intermediate cans. FIGS. 2a and 3 show an exemplary can 101, which may be produced on the assembly line 1 in FIG. 1. It is to be understood that the particular shape of the can 101 shown in FIG. 3 should not be considered limiting to the invention, as the assembly line 1 is suitable for the production and filling of cans of any useful shape or size and for the production of composite cans without such components which are disclosed herein as being optional.

The illustrated assembly line 1 comprises a number of machine units 3-10 connected by conveyors 2 a, 2 b, 2 c, 2 d. In order from the beginning of the assembly line 1, the machine units are: a body forming unit 3, a filling unit 4, a gas box 5, a sealing unit 6, a cleaning unit 8, a can turning unit 9, a scoop insertion unit 10 and a lid attachment unit 7. A further conveyor 2 e is arranged at the end of the assembly line 1 and is arranged to convey the produced composite cans from the lid attachment unit 7 and further e.g. to a packing apparatus (not shown).

Production of composite cans on the assembly line 1 is described below with reference to a single composite can. It is to be understood that while the assembly line 1 is run, multiple composite cans are continuously produced and are leaving lid attachment unit 7 at the end of the assembly line 1. As set out herein, the machine units of the assembly line 1 such as any can component attachment unit, may be configured to simultaneously process multiple intermediate cans such as 2, 3, 4, 5 or 6 intermediate cans. Exemplary can component attachment units 405, 406 are shown in FIGS. 5, 6 and 7.

The body forming unit 3 includes: a body blank picking station 11, a body forming station 12, a top sealing station 13 and a top rim application station 14.

In the body blank picking station 11, a body blank 16 is picked from a pile of body blanks 16 and transferred to the body forming station 12. In the body forming station 12 a tubular body is formed by bending the body blank 16 and bringing two opposing edges of the body blank together in an end-to-end join, also known as a “butt join”. The join extends in a height direction H of the tubular body between a top end and a bottom end of the tubular body, as shown in FIG. 2a . The join is subsequently sealed by means of a sealing strip which is welded to the inner surface of the tubular body, whereby an intermediate can is formed. The sealing strip and the inner surface of the tubular body comprise a weldable polymer layer on the adjoining surfaces. The sealing strip is preferably welded to the inner surface of the tubular body by means of high frequency induction welding, as disclosed herein.

After forming the tubular body and applying the sealing strip, the intermediate can is transferred to the top sealing station 13 and the top opening at the top end of the tubular body is sealed by attaching a top sealing member across the top opening. The top sealing member is attached by welding a peripheral flange of the top sealing member to the inner surface of the tubular body. As disclosed herein, the top sealing member is commonly a flexible component made from a laminate of one or more layers of aluminium foil and outer layers of thermoplastic polymeric material and the peripheral flange is created by folding an edge portion of the top sealing member out of the plane of the top sealing member and into alignment with the inner surface of the tubular body. The top sealing member is taken from a magazine which is not visible in FIG. 1 and is applied at a distance from the top opening edge to allow for attachment of a top rim above the top sealing member. If the composite can comprises a scoop, a leaflet, or other supplementary item, the top sealing member may be applied at a sufficient distance from the top opening edge to allow the item to be accommodated in a space formed between the top sealing member and an inner surface of the reclosable lid.

The intermediate can with the applied top sealing member is then transferred to the top rim application station 14 where the top rim is applied to the intermediate can by inserting at least a lower part of the top rim into the top opening, above the top sealing member. Preferably, the top rim is inserted into the tubular body such that an upper end edge of the top rim remains outside of the tubular body or is flush with the top end edge of the tubular body whereby the top rim protects the vulnerable carton edge of the tubular body and forms a rigid resting surface for the intermediate can during the subsequent process steps.

As illustrated in FIG. 1, the body forming unit 3 is enclosed in an external housing 20. A can turning arrangement may further be arranged inside the external housing 20 so that the intermediate can with the top rim attached may be turned upside down directly after rim application. Alternatively, the intermediate can is turned in a conventional turning apparatus placed downstream of the top rim application station 14. An example of a conventional turning apparatus is illustrated by the can turning unit 9, which is located downstream of the body forming unit 2. The can turning unit 9 operates by causing the intermediate can to topple over on an inclined conveyor.

After application of the top rim and turning the intermediate can upside down, the intermediate can is transferred to a first conveyor 2 a and placed with the top rim resting on the conveyor 2 a and a bottom opening at a bottom end of the tubular body facing upward in the vertical direction. The intermediate can is moved by the conveyor 2 a to the filling unit 4 where it is filled with dry or moist goods through the bottom opening of the tubular body.

Subsequently, while still resting on the top rim, the filled intermediate can is moved by a second conveyor 2 b to the gas box 5 where the filled intermediate can is subjected to treatment by a protective gas while the intermediate can is moved through the gas box 5. The gas box 5 is an optional part of the process equipment for carrying out the method as disclosed herein which may be used e.g. when the packaged goods is sensitive to oxygen and/or moisture. Furthermore, creating a protective gas atmosphere for the filled intermediate can may be made by other means, as set out herein. After leaving the gas box 5, the filled intermediate can is transferred to the sealing unit 6 on a third conveyor 2 c. The third conveyor 2 c moves through a gas tunnel which is tightly fitted to the wall of the sealing unit 6 at the inlet into the sealing unit 6, in order to maintain the protective atmosphere created in the gas box 5.

In the sealing unit 6, the bottom opening of the tubular body is sealed in a can sealing station 21 by attaching a bottom sealing member across the bottom opening, the attachment being made by welding a peripheral flange of the bottom sealing member to the inner surface of the tubular body at a distance from a bottom end edge of the tubular body. Accordingly, the bottom sealing member is applied in a manner corresponding to that of the top sealing member by folding a peripheral edge portion of the bottom sealing member into alignment with the inside wall of the tubular body before welding the facing surfaces of the bottom sealing member and the tubular body to each other. The sealing unit 6 preferably comprises a rim application station 22 for application of a bottom rim after the bottom sealing member has been inserted in the tubular body and welded in place. As disclosed herein, application of a bottom rim is an optional operation which may be performed on the intermediate can.

As is seen in FIG. 1, the sealing unit 6 is enclosed in an external housing 23, similar to the external housing 20 which encloses the body forming unit 3. By adapting the size and shape of the inlet and outlet ports 24, 25 of the external housing 23 to the size and shape of the intermediate cans produced on the assembly line 1, the ports 24, 25 may be kept generally sealed by the intermediate cans continuously passing through the ports 24, 25 during production. Thereby, it is possible to maintain a protective gas atmosphere inside the external housing 23 during the bottom sealing operation.

After filling, bottom sealing, and optional application of a bottom rim, the intermediate can is again turned to bring the top rim in an upward-facing position in the vertical direction.

In analogy with the first turning operation which is carried out after application of the top rim, the can turning arrangement may be part of the sealing unit 6 so that the intermediate can is turned directly after bottom sealing and optional bottom rim application. In the assembly line 1 which is shown in FIG. 1, the intermediate can is instead turned in a conventional turning unit 9 which is arranged downstream of the sealing unit 6.

In the example shown in FIG. 1, a cleaning unit 8 is arranged between the sealing unit 6 and the turning unit 9. In the cleaning unit 8, any product residue which may have escaped to the outside of the intermediate can during the previous process steps is removed by means of pressurized air. A cleaning unit 8 is optional to the assembly line as disclosed herein and may be particularly useful when the packaged goods is a powder or a particulate material with small-size particles or containing fragments which may cause dusting.

As set out herein, a scoop or other item may be placed above the top sealing member before finally closing the composite can by attaching the lid. As shown in FIG. 1, a scoop insertion unit 10 and/or other item insertion unit may be arranged in the process line, downstream of the location where the composite can has been turned with the top end facing upward. In the assembly line shown in FIG. 1, the scoop insertion unit 10 is placed after the turning unit 9.

The filled and sealed intermediate can is thereafter transported to the lid attachment unit 7 on the conveyor 2 d and a reclosable lid is attached at the top end of the tubular body such that an inner surface of the reclosable lid is in direct contact with an upper surface of the top rim. As set out herein, the reclosable lid may be applied as part of a lid component, the lid component further comprising a frame structure. Preferably, the lid component is mechanically attached to the upper rim by a snap-fit connection.

The assembly line may further comprise quality control equipment and equipment for removing deficient intermediate composite cans and fully assembled composite cans from the flow of composite cans. Such quality control equipment may comprise detection equipment for detecting flaws in the intermediate cans or machine malfunctioning during production e.g visual detection devices, an X-ray machine which may be placed after the lid attachment unit 7, etc. Furthermore, the quality control equipment may comprise can rejection stations which are commonly placed after one or more of the body forming unit 3, the filling unit 4, the sealing unit 6, the scoop insertion unit 10 and the lid attachment unit 7 to ascertain that any deficient composite cans are removed from the production line.

As disclosed herein, the composite cans are filled with dry or moist goods in the form of particles or pieces, granules, flakes, grain, etc. The goods flows into the composite can under the influence of gravity.

The composite can 201 shown in FIGS. 2a and 3 may be produced on the assembly line 1 in FIG. 1 and comprises a tubular body 203 having a tubular body wall 205. The body wall 205 extends in the height direction H of the can 201 from a bottom end edge 207 at a bottom end of the tubular body 203 to a top end edge 209 at a top end of the tubular body 203. The tubular body 203 has a top opening 211 at the top end and a bottom opening 213 at the bottom end.

A bottom sealing member 215 is positioned at the bottom end of the tubular body 203 and covers the bottom opening 213. The tubular body 203 has been formed by bringing together the side edges of a body blank end-to-end and sealing the join with a sealing strip 214, as set out herein.

The bottom end edge 207 is reinforced by a reinforcing bottom rim 217 which is applied to the inner surface of the body wall 205 and/or to a peripheral flange 216 of the bottom sealing member 215, between the bottom sealing member 215 and the bottom end edge 207. In the illustrated embodiment, the bottom rim 217 has an outwardly directed flange 219 which covers the bottom end edge 207 of the tubular body 203 and forms a bottom edge of the can 201. The bottom rim 217 reinforces the bottom end edge 207, stabilizes the shape of the tubular body 203 and protects the bottom edge 207 from mechanical deformation. The bottom rim 217 also serves as a protective barrier against water and other fluids which may be present on a surface on which the can 201 is placed. The bottom rim 217 delimits a downwardly open space between the bottom sealing member 215 and the bottom edge of the can 201, which may be used to accommodate stacking elements arranged at an upper end of another can when stacking two or more cans on top of each other. The reinforcing bottom rim 217 is an optional component of the composite can as disclosed herein.

As an alternative to the illustrated bottom rim 217, the bottom edge of the composite can 201 may be formed by a rolled edge of the tubular body 203, or may be provided by a simple, non-rolled join between the bottom sealing member 215 and the tubular body 203.

The composite can 201 is provided with a closure arrangement comprising a lid 221 and a top rim 223 extending along the edge of the top opening 211. The lid 221 comprises a planar inner sealing disc 225 which seals against the top rim 223 when the composite can 201 is closed, as shown in FIG. 3. The can 201 is further provided with a fully or partly removable top sealing member 227 which is sealed to the body wall 205 along an upwardly folded peripheral flange 218.

The bottom rim 217 and the top rim 223 are made of plastic material, preferably thermoplastic material and form closed loops, as seen in FIG. 2 a.

The top rim 223 defines a perimeter of an access opening which is smaller than the upper container body opening 211 as defined by the upper end edge 209 of the tubular body 203.

As set out herein, the top rim 223 is attached to an inner surface of the body wall 205 at the top opening 211. The top rim 223 has an extension in the height direction, H, of the composite can 201 and has a lower rim part facing towards the bottom sealing member 215 and an upper rim part facing away from the bottom sealing member 215. The top rim 223 extends around the full periphery of the top opening 211. The upper part of the top rim 223 protrudes upwards in the height direction, H, above the top end edge 209, whereby a part of the top rim 223 is arranged above the top end edge 209 in the height direction, H, of the composite can 201.

The top rim 223 is joined to the inner surface of the body wall 205 by means of a weld seal extending around the top opening 211. The weld seal preferably extends continuously around the top opening 211 and is a sift-proof weld seal and is preferably also a moisture proof weld seal and most preferably a gas-tight weld seal.

As set out herein, the weld seal between the top rim 223 and the body wall 205 is formed by supplying energy to heat and locally soften or melt one or more thermoplastic component in the top rim 223 and/or in a coating or film on the inner surface of the body wall 205 and by pressing the top rim 223 and the body wall 205 together in a direction perpendicular to the body wall 205. The temperature and pressure can be controlled and adjusted to form a strong and tight seal without damaging the welded components. The thermoplastic material used to create the weld seal may be provided by a fully or partly thermoplastic top rim 223, by a thermoplastic film or coating on the inner surface of the body wall 205, or by thermoplastic material from both the top rim 223 and the body wall 205. The top rim 223 is preferably made from thermoplastic material which allows it to be thermoformed, e.g. by injection molding. An injection molding process may be used to form plastic components having different polymer compositions in different parts of the plastic component. By way of example, the surface of a plastic top or bottom rim which is to be welded to the container body may be formed from a polymer composition having a lower softening and melting point than other parts of the rim. Moreover, an abutment surface on the top rim 223 may be formed from a resilient thermoplastic polymer. Any suitable welding technique may be used, such as ultrasonic welding or high frequency induction welding, with high frequency induction welding being preferred, as set out herein.

The lid 221 is a profiled part with a three-dimensional shape providing an upper outer surface of the lid 221. The lid may have an inner surface comprising a pattern of reinforcing ribs. The composite can shown in FIG. 2a comprises a planar sealing disc 225 which is applied over the inner surface of the lid 221. The sealing disc 225 is arranged to seal against the upper part of the top rim 223 when the composite can 201 is in the closed position as shown in FIG. 3. Alternatively, an inner sealing surface of the lid may be formed integral with the lid. Further alternatives for creating a sealing closure between the top rim 223 and the lid 221 is by arranging a sealing ring on the inner surface of the lid 221 or by application of a sealing coating on selected portions of the inner surface of the lid and/or on the top rim 223.

The lid 221 is connected by a hinge 229 to a frame structure 230, the lid 221 and the frame structure 230 together forming a lid component 231. The hinge 229 is a live hinge, formed integrally with the lid 221 and the frame structure 230 as a flexible connection between the lid 221 and the frame structure 230. As set out herein, the illustrated hinge is only intended as a non-limiting example and it should be understood that any other type of functional hinge may be used for a connection between the frame structure and the lid.

Moreover, the lid may be of the removable kind, without any permanent connection to the frame structure.

The frame structure 230 is applied to the composite can 201 at the top end edge 209 and is mechanically attached to the top rim 223 by a snap-on connection. The frame structure 230 is attached to the top rim 223 after the top rim 223 has been welded to the inner surface of the body wall 205. The frame structure 230 is applied to the top rim 223 by pressing the frame structure 230 down over the upper edge of the top rim 223 until the frame structure 230 locks in place on the top rim 223 by means of mating snap-in features on the top rim 223 and the frame structure 230. When the frame structure 230 has been attached to the top rim 223, it can only be removed again by breaking or damaging the snap-in connection between the top rim 223 and the frame structure 230.

An interior compartment 208 containing the packaged goods is delimited by the top sealing member 227 at the upper end of the tubular body 203 and by the bottom sealing member 215 at the bottom end of the tubular body 203.

In order to gain a first access to the packaged goods in the interior compartment 208, a user needs to open the lid 221 and expose the packaged goods by fully or partly removing the top sealing member 227. The top sealing member 227 may be arranged to be peeled away from the wall 205 of the tubular body 203 or may be arranged with means for breaking the top sealing member 227 so that it can be at least partly removed through the access opening. Such means may be in the form of one or more predefined weakenings, such as perforations or a cut partly through the top sealing member 227. When the top sealing member 227 is of the tear-open type, a narrow edge part of the top sealing member 227 may be left at the inner surface of the body wall 205. Any such remaining part of the top sealing member 227 should preferably not be so large so that it extends into and restricts the access opening which is defined by the inner perimeter of the top rim 223.

Once the top sealing member 227 has been removed, it is sufficient to open the lid 221 in order to gain access to the packaged goods in the interior compartment 208 through the access opening. As is seen in FIG. 2a , which reveals the inside of the top rim 223, the area of the access opening is defined by an inner perimeter or inner contour of the top rim 223. As the top rim 223 is applied on the inner surface of the body wall 205 and adds thickness to the body wall in an inward direction, the area of the access opening is always smaller than the area of the top opening 211 of the tubular body 203.

When the composite can 201 is open, a desired quantity of the packaged goods may be removed from the composite can 201 through the access opening either by means of a scoop or by pouring. The scoop may preferably be provided together with the composite can 201. The scoop may initially be placed on the top sealing member 227, may be removably attached to the inner surface of the lid 221 which inner surface is constituted by the sealing disc 225 in the example shown in FIG. 2a . When placed on the top sealing member 227, the scoop may be packaged in a protective wrap, such as a bag of paper or plastic. A further alternative is to attach a scoop to the top rim 223 e.g. by placing the scoop head in a scoop holder 240 provided on the top rim 223 as shown in FIG. 2a . In the illustrated embodiment, the scoop holder 240 also serves as a scraper bar for levelling off excess scooped-up material from the scoop. An example of a scoop 280 is shown in FIG. 2b . The scoop 280 has a scoop head 281 and a scoop handle 282. Generally, scoops 280 to be inserted into an intermediate can during manufacturing of a composite can as disclosed herein are arranged in a stack, e.g. as shown in FIG. 2b with the scoop heads 281 nesting inside each other. In order to facilitate stacking of scoops 280 with planar handles 282 a proximal end of the handle 282 may be provided with a stack stabilization arrangement 284. The stack stabilization arrangement 284 allows stacking of identical scoops 280 inside each other and facilitates keeping the stack 283 of scoops together, simplifying storing and handling of the scoops 280 and loading of the scoops into a scoop insertion unit 10, as shown in FIG. 1.

Advantageously the scoop head 281 has a tapering shape to allow she scoops 280 to fit snugly inside each other in an efficient and space saving manner.

As an alternative to stacking the scoops 280 with the scoop heads 281 and the scoop handles 282 arranged in the same direction, the scoops 280 may be stacked in alternating opposite directions as known in the art.

It is to be understood that the scoop 280 which is shown in FIG. 2b constitutes only one example of a suitable scoop configuration and that scoops having differently shaped scoop heads, differently shaped handles, different proportions between the scoop head and the scoop handle, etc. may be used in the composite cans as disclosed herein. The scoop may further have provisions for additional stack stabilization and/or for improving retention of the scoop 280 in a scoop holder. By way of example, the scoop head may comprise a thin snap-in ridge which serves to releasably lock the scoop head in a desired position in the scoop holder. Such additional fastening element for the scoop head may prevent the scoop head from inadvertently falling out of the scoop holder, and may also serve to prevent the scoop handle from hanging down into the composite can.

The closure arrangement as shown on the composite can 201 in FIGS. 1 and 2 a with a top rim 223 directly attached to the inner surface of the body wall 205 and a lid component 230 comprising a lid 221 and a frame structure 230 provides a tight closure between the lid 221 and the tubular body 203. When the lid 221 is closed on the composite can 201, the upper edge of the top rim 223 abuts against the sealing disc 225 and creates a seal between the top rim 223 and the lid 221.

In order to keep the lid 221 secured in the closed position between dispensing occasions, the closure arrangement of the composite can 201 may further comprise a locking arrangement 245, as seen in FIGS. 2a and 3. The locking arrangement 245 may comprise first and second mating locking elements, e.g. a female locking element such as a groove arranged on the lid 221 and a male locking element such as a rib arranged on a locking member 246 arranged on the frame structure 230. The locking member 246 is hingedly connected to the frame structure 230, such as by means of a live hinge 249 formed integrally with the frame structure 230 and the locking member 246.

A locking arrangement 245 of this type is closed by moving the locking member 246 upward and inward over the lid 221 to a position where the locking elements come into mating engagement. The locking arrangement 245 is opened by pulling at the locking member 246 until the connection between the locking elements is released and turning the locking member 246 downward at the hinge 249. When the locking member 246 is in the closed position with the first and second locking elements engaging with each other, the lid 221 and the frame structure 230 are firmly clamped together whereby the top rim 223 seals tightly against the sealing disc 225 on the inner surface of the lid 221, or against a sealing ring or sealing surface arranged on the inside of the lid 221.

As best shown in FIG. 3, the lid component 231 is provided with a lid component stacking step 251 and a can stacking step 252. As shown in the figures, the stacking steps 251, 252 may extend across the locking member 246.

The lid component stacking step 251 is arranged to enable stacking lid components 231 on top of each other in stacks which can be loaded into a lid attachment unit. The can stacking step 252 is arranged for enabling stacking of composite cans 201 on top of each other.

An inset gripping area 265 may be arranged in the lid 221 at the free end portion of the locking member 246, opposite the hinge 249. Thereby, the locking member 246 can be easily accessed and while the locking member 246 when in the closed position is shielded from inadvertent release.

A composite can 201 as shown in FIGS. 2a and 3 may be produced and filled on an assembly line such as that shown in FIG. 1.

As set out herein, the composite cans as disclosed herein are produced in the following order: forming a tubular body, applying a top sealing member and a top rim to the tubular body, turning the tubular body upside down, filling the tubular body with dry or moist goods through the bottom opening of the tubular body, closing the bottom opening of the tubular body, optionally applying a bottom rim to the tubular body, turning the sealed can so that the top sealing member again faces upward and finally applying a lid or a lid component to the top end of the tubular body.

FIGS. 4-7 show equipment which may be used for the application of can components in a top sealing station 13, a top rim application station 14, a sealing unit 6 and a bottom rim application station 22 of an assembly line 1 as shown in FIG. 1.

With reference to FIGS. 2a and 3, the bottom sealing member 215, the bottom rim 217, the top rim 223 and the top sealing member 227 are examples of can components for which the equipment in FIGS. 4-7 may be used.

With reference to FIG. 4, a can sealing unit 401 which may be the sealing unit 6 in FIG. 1 is shown.

Intermediate cans 403 are transported through the can sealing unit 401 in a running direction R. Transport means 402 comprising a feeding arrangement 411 in the form of two feed screw members arranged at respective opposite sides of the intermediate cans 403, whereof only one of the feed screw members is visible in FIG. 4, a main conveyor member 413, a movable gripping arrangement 415, and an outlet conveyor member 419. The outlet conveyor member 419 is arranged downstream of the can sealing unit 401 and a stationary sliding plate 421 is arranged downstream of the outlet conveyor member 419 at the outlet of the can sealing unit 401. Further details of a useful transport arrangement are described in WO 2013/009226 A1, to which document reference is made.

A can sealing station 405′ is located downstream of the feeding arrangement 411 and a bottom rim application station 405″ is located downstream of the can sealing station 405′. The movable gripping arrangement 415 move the intermediate cans 403 to the sealing station 405′ where bottom sealing members 427 are attached by welding to the inside of the tubular body wall of the intermediate cans 403, as illustrated by FIG. 8. The intermediate cans 403 are then moved to the bottom rim application station 405″, where bottom rims 417 are applied, e.g. as shown in FIGS. 5 and 6 As illustrated in FIGS. 4-6 a plurality of bottom sealing members and bottom rims 417 may be attached simultaneously to a plurality of corresponding intermediate cans 403, in order to increase the running speed of the can sealing station 401. In the shown embodiment, four bottom sealing members and four rims are attached at the same time to respective intermediate cans 403. Alternatively, the bottom sealing members, rims or other can components as disclosed herein may be attached in groups of any other number than four, e.g. two, three, six, eight or ten, at the same time, or may be sequentially attached to the cans.

The transport means 402 and the can sealing station 401 may be encased in an external housing 20, 23 as shown in FIG. 1. The external housing 20, 23 is adapted to protect the can sealing station 401 and/or to provide and maintain a protective gas atmosphere inside can sealing station 401. The protective gas may e.g. be nitrogen, carbon dioxide or a mixture of nitrogen and carbon dioxide.

Degassing of the intermediate can may be performed concurrently with filling the intermediate can in a filling unit 4 as shown in FIG. 1. The degassing may comprise supplying a protective gas to the flow of material to be contained in the can during filling. The protective gas may be blown into the flow of material before the material reaches the can. If the material is treated with protective gas during filling, the intermediate cans 403 are preferably conveyed to a can component applicator such as the can sealing station 401 arranged downstream of the filling unit 4, while maintaining the modified gas atmosphere, e.g. by moving the cans through a tunnel filled with protective gas as illustrated by the covered conveyor 2 c between the gas box 5 and the sealing unit 6 in FIG. 1. Alternatively, filled intermediate cans 403 may be introduced in a vacuum chamber to draw off air, whereafter the cans are subjected to a modified gas atmosphere and the bottom sealing member is applied.

FIGS. 5 and 6 illustrate an attachment unit 505 for attaching a can component such as a bottom rim 517 to an intermediate can 503. The attachment unit 505 comprises a retaining device 523, a supporting device 525, a positioning device 528 and a transfer plate 529.

An example of a transfer plate 529 is illustrated in FIG. 7. The transfer plate 529 extends in a first direction x, parallel to the running direction R of a can component applicator of which the attachment unit 505 forms part, and a second direction y perpendicular to the first direction x. The transfer plate 529 comprises a cavity portion 531 with at least one through-going transfer cavity 533 which is adapted to receive and hold the can component, in this case a bottom rim 517 during transfer of the can component into alignment with an end of the intermediate can 503. The transfer cavity 533 has a first open area A₁ and is sized and configured such that the can component can be fit into the transfer cavity 533 and be retained therein during transfer to the intermediate can 503.

As an alternative, in particular when the can component is a sheet form can component such as a top sealing member or a bottom sealing member, the transfer plate 529 may be omitted such that the can component is placed directly on top of the retaining device 523.

In order to fit and hold the can component in the transfer cavity 533, the shape of the transfer cavity 533 is made to correspond to the shape of the can component.

In case of a can component including an edge portion which is to be folded to create a peripheral flange before or during insertion of the can component in the can, as is the case in a bottom sealing member or a top sealing member, the first open area A₁ of the transfer cavity 533 may be smaller than the surface area of the can component before folding. The area difference corresponds to the area of the portion of the can component which forms the peripheral flange. Such a folded flange is typically band shaped and may have a width in the range of from 1 to 10 mm, such as in the range of from 2 to 5 mm. See FIG. 8. Accordingly, a folded peripheral flange on a sheet form can component such as a top sealing member or a bottom sealing member may be created by pressing the can component down through a transfer cavity 533 having a smaller cross-sectional area than the can component, thereby forcing the can component to fold at the edge of the transfer cavity in order to be accommodated within the first open area A₁ of the transfer cavity.

A wall of the transfer cavity 533 may comprise holding elements 534 adapted to hold the can component in the transfer cavity 533. See FIG. 7. Such holding elements 534 are especially useful for a loop shaped can component such as a top or bottom rim which does not cover the first open area A₁ of the transfer cavity 533. When the can component is a sheet form can component, the holding elements 534 may be omitted.

In the embodiment illustrated in FIG. 7, there are four holding elements 534 each adapted to hold a corresponding side of a loop shaped can component having a substantially rectangular or square shape. In the illustrated embodiment the holding elements 534 are arranged such that they will hold the can component at a centre of each side. It would be feasible to use one, two, three, four or more such holding elements 534. The holding elements 534 may be resiliently compressible, e.g. due to material properties or by being biased by a spring. Alternatively or additionally, the can component such as a rim may itself be resiliently deformable, e.g. due to material properties. The holding elements 534 may be utilized to compensate for tolerances regarding the dimensions of the can component and/or the transfer cavity 533. Furthermore, the holding elements 534 may be used to temporarily press one or more sides of the can component inwards, causing the can component to assume a reduced cross-section whereby it is easier to insert into the intermediate can 503. Thereby, the risk of damaging the vulnerable carton edges of the tubular body of the intermediate can 503 during insertion of a rim-type can component can be eliminated or at least considerably reduced.

As illustrated in FIGS. 5, 6 and 7, the transfer plate 529 may comprise a cover portion 535 which is at least as large as, or substantially as large as, the first open area A₁ of the transfer cavity 533. The cover portion 535 is arranged adjacent to the cavity portion 531 as seen in the second direction y. The cover portion 535 has a minimum extension y₁ in the second direction y, which is at least 1.0 times a maximum extension y₂ in the second direction y of the area A₁ of the transfer cavity 533, preferably at least 1.2 times, more preferably at least 1.4 times. The use of a transfer plate having a cover portion 535 is advantageous to prevent excessive escape of protective gas from inside a can component applicator while the can component is being placed in the transfer cavity 533 and transported into alignment with the intermediate can 503. When the can component is instead a sheet form component, it may be picked by a suction member and placed in alignment with an opening in the intermediate can 503 in which the sheet form can component is to be inserted. As set out herein, the transfer plate 529 may be omitted and the sheet form can component may be placed directly on top of the retaining device 523.

After application in the intermediate can 503, the sheet form can component covers the can opening and prevents gas from escaping out through the intermediate can 503. If the can component applicator is operated without a protective atmosphere or if some loss of protective gas can be tolerated, a transfer plate without a cover portion may be used when applying the can component. Furthermore, the attachment unit 505 may comprise an internal housing 547, as indicated by point-dashed lines in FIGS. 5 and 6. The internal housing 547 is located inside an external housing 20, 23 as shown in FIG. 1 and is arranged to provide enhanced protection against escape of protective gas from the space above the positioning cavity 537 of the retaining device 523.

In order to facilitate placing a can component into the transfer cavity 533 of the transfer plate 529, indentations 536 may be provided as illustrated in FIG. 7. The indentations 536 allow space for gripping members 544 a, 544 b, 544 c, 544 d which are arranged to move the can component from a magazine 543 into the transfer cavity 533. See FIGS. 5 and 6. If holding elements 534 are provided in the transfer plate 529, the indentations 536 are preferably located such that they do not interfere with the holding elements 534. Thus, the indentations 536 may be located in the corners of the transfer cavity 533. Such gripping members 544 a, 544 b, 544 c, 544 d with their corresponding indentations 536 are especially useful when the can component forms a loop, which comprises an inner volume filled by gas, e.g. air, such as a bottom rim or a top rim.

If the can component is a sealing member, or a lid, the can component may instead be placed into the transfer cavity 533 by gripping means such as one or more suction cups. In such case, the indentations 536 may be omitted. However, suction cups are not suitable when the can component is of the loop type, such as a top or bottom rim.

In the illustrated embodiment, which may e.g. be a bottom rim application station 22 of an assembly line 1 as shown in FIG. 1, there are four cavity portions 531 arranged in a row as seen in the first direction x. Each cavity portion 531 comprises a respective transfer cavity 533 and is arranged together with a corresponding respective cover portion 535.

The retaining device 523 retains the intermediate can 503 while the can component, illustrated as the bottom rim 517, is being attached to the intermediate can 503. The retaining device 523 comprises at least one through-going positioning cavity 537 with a second open area A₂ corresponding to the first open area A₁ of the transfer cavity 533.

The positioning cavity 537 is adapted to receive a portion of the intermediate can 503. If having a cover portion 535, the size and shape of the cover portion 535 of the transfer plate 529 is selected, such that the cover portion 535 can be brought to cover, or at least substantially cover, the second open area A₂ of the positioning cavity 537.

The supporting device 525 is arranged to support the intermediate can 503 and to position the intermediate can 503 in the retaining device 523.

The positioning device 528 is arranged to position the can component in the intermediate can 503 as illustrated by FIGS. 5 and 6. Hence, the positioning device 528 is aligned with the positioning cavity 537 as seen in a vertical direction z. The positioning device 528 is vertically adjustable allowing insertion of the can component into the intermediate can 503 to a desired preselectable attachment position. As described herein with reference to FIG. 8, the positioning device 528 may be caused to expand in a radial direction of the positioning cavity 537 and to press a vertically extending portion of the can component in a direction towards a wall of the positioning cavity 537, whereby the can component is pressed against an inside of the tubular wall of the intermediate can 503 which is placed in the positioning cavity 537.

In the illustrated embodiment the attachment unit 505 is arranged to simultaneously process four intermediate cans 503. The transfer plate 529 comprises four cavity portions 531 arranged in a row as seen in the first direction x of the attachment unit 505. In a corresponding way, the retaining device 523 comprises four positioning cavities 537, and the supporting device 525 is adapted to support four intermediate cans 503 and to position the intermediate cans 503 in the respective positioning cavities 537 of the retaining device 523. In addition, the attachment unit 505 comprises four positioning devices 528, aligned with the positioning cavities 537, such that each positioning device 528 is associated with a respective positioning cavity 537. It is to be understood that the attachment unit may be arranged for simultaneous processing of any suitable number of intermediate cans, as set out herein.

The transfer plate 529 is movable between a first position shown in FIG. 5 and a second position shown in FIG. 6. In the first position, the transfer plate 529 has been moved in the y-direction such that the transfer cavity 533 has been shifted away from the retaining device 523. In this position, the transfer plate 529 is arranged to receive the can component in the transfer cavity 533. If the transfer plate 529 is provided with a cover portion 535, as shown in FIGS. 5-7, the cover portion 535 in the first position covers or substantially covers the second open area A₂ of the positioning cavity 537, as illustrated in FIG. 5 during application of the can component in the transfer cavity 533. Thereby, loss of protective gas through the positioning cavity 537 may be minimized, or preferably eliminated.

In the second position, as shown in FIG. 6, the transfer plate 529 has been moved in the y-direction whereby the transfer cavity 533 has been brought into alignment with the positioning cavity 537 of the retaining device 523 and the positioning device 528 which is arranged above the positioning cavity 537. When the transfer plate 529 is in the second position, the positioning device 528 may push a can component located in the transfer cavity into the intermediate can. The can component, such as the bottom rim 517 shown in FIGS. 5 and 6, is pushed from the transfer cavity 533 in the transfer plate 529 into the intermediate can 503 by downward movement of the can component in the z direction through the transfer cavity 533 and at least partly through the positioning cavity 537 of the retaining device 523.

The retaining device 523 may comprise a welding unit 539 as disclosed herein. The welding unit is preferably a high frequency induction welding unit and is arranged around the positioning cavity 537. The welding unit 539 is adapted to weld the can component to the intermediate can 503, and comprises a coil extending around the positioning cavity 537. As the positioning device 528 may be caused to expand in a radial direction of the positioning cavity 537 as set out herein, the can component can be pressed against the welding unit 539.

As is shown in FIGS. 5 and 6, the bottom rim 517 or other can component may be placed in the transfer cavity 533 of the transfer plate 529 by means of an optional can component supplier 541 comprising at least one gripping unit 542. A pile of can components, e.g. bottom rims 517, may be stored in a magazine 543. The number of piles in the magazine 543 and the number of gripping units 542 correspond to the number of transfer cavities 533 in the transfer plate 529. The gripping unit 542 is able to grip a single can component, here the bottom rim 517, move it from an opening 545 in the magazine 543 and place it in the corresponding transfer cavity 533. As an example, four single can components are gripped at the same time. The gripping unit 542 comprises four gripping members 544 a, 544 b, 544 c, 544 d, which grip at the corners of the bottom rim 517. The positions of the gripping members 544 a, 544 b, 544 c, 544 d correspond to the positions of the indentations 536 of the transfer plate 529. As set out herein, such gripping members 544 a, 544 b, 544 c, 544 d with their corresponding indentations 536 are especially useful when the can component is not a sheet form element such as a bottom sealing member, an internal sealing member, or a top sealing member, but instead forms a loop, such as a top rim or a bottom rim.

FIG. 8 illustrates a positioning device 828 as disclosed herein. The positioning device 828 may be used as a positioning device 528 of an attachment unit 505 as illustrated in FIGS. 5 and 6 or may be used for positioning of a can component in any attachment unit used for attachment of a can component inside a tubular can body. Hence, the positioning device may be used for placing can components in a tubular body with or without the concurrent use of a transfer plate.

FIG. 8 illustrates a top sealing member 827 which is in the process of being placed in an intermediate can 803. As can be gleaned from FIG. 8, the top sealing member 827 has a larger cross-sectional area than the inner cross-sectional area of the intermediate can 803. When placed in the intermediate can 803, an edge portion 833 of the top sealing member 827 will be folded upwards, such that it conforms to an inner surface of the can wall 805. The illustrated top sealing member 827 is a foldable member, such as a laminate of plastic film and aluminium foil, a plastic film, a paper sheet, a paper/plastic laminate, or the like. Can components such as top sealing members and bottom sealing members may alternatively be pre-formed with a sealable edge portion extending perpendicular to a main plane of the of the can component. In such case, no folding of the edge portion is needed when inserting the can component into the tubular can body.

The positioning device 828 comprises a base plate 849 comprising or being constituted by a rigid material such as metal or a composite material, and a plunger skirt 851 comprising a resiliently deformable material, e.g. rubber or plastics. The plunger skirt 851 is located on top of the base plate 849, such that it at least partly covers an upper surface of the base plate 849 which upper surface is opposite a lower footprint surface 853 of the base plate 849.

The footprint surface 853 is configured to face towards the can component, here a top sealing member 827, during application of the can component in the intermediate can 803. The footprint surface 853 of the base plate 849 has a circumferential edge 855 which in the illustrated example has a substantially polygonal shape. However, it is to be understood that the footprint surface may have any other suitable shape adapted to the cross-sectional shape of the composite can which is being produced. In the illustrated example, the substantially polygonal shape is a substantially square shape which comprises four side edge portions which are connected by outwardly rounded corner portions. In the illustrated embodiment, each side edge portion is slightly inwardly curved. Thereby, the circumferential edge 855 of the footprint surface 853 of the base plate 849 with the inwardly curved side edge portions deviates from the cross-sectional shape or footprint of the produced composite can. Alternatively, the base plate of the positioning device may have the same footprint as that of the intermediate can 803, with straight side edge portions between curved corner portions.

It may be advantageous to arrange a curved side edge portion at least on the side of the base plate 849 which during insertion of the can component will be facing the sealing strip 814 covering the join in the tubular body 805. The sealing strip 814 makes the tubular wall 805 of the intermediate can 803 locally thicker and also constitutes a bending line where the tubular wall 805 tends to bend causing the tubular wall 805 to deviate from a desired planar or near-planar shape. A slightly inwardly curved side edge portion of the circumferential edge of the footprint surface of the base plate, allows the base plate to move along the join without damaging the sealing strip or the can body material when the positioning device 828 inserts the can component 827 into the intermediate can 803.

The plunger skirt 851 is transformable between an unexpanded state and an expanded state by relative movement in relation to the base plate 849.

In the unexpanded state of the plunger skirt 851, the shape of the outer contour of the plunger skirt 851 corresponds to that of the base plate 849. Hence, in the unexpanded state, the plunger skirt 851 has the same or substantially the same footprint as the base plate 849.

When seen in relation to the base plate 849, the outer circumference 861 of the plunger skirt 851 is located at or on the circumferential edge 855 of the base plate 849. Preferably, the outer circumference 861 of the plunger skirt 851 coincides with the circumferential edge 855 of the footprint surface 853 of the base plate 849 or is located slightly inside the circumferential edge 855 of the footprint surface 853 of the base plate 849 when the plunger skirt 851 is in the unexpanded state.

In the expanded state of the plunger skirt 851, the footprint which is delimited by the outer circumference 861 of the plunger skirt 851 is larger than in the unexpanded state of the plunger skirt 851.

During transformation to the expanded state, pressure is applied to the plunger skirt 851 from above. Thereby, the side edge portions of the plunger skirt 851 are stretched between the corners and any curved side edge portion is thereby straightened out. By selecting the shape and material properties of the plunger skirt 851, a desired change of shape during transformation may be obtained.

In the expanded state of the plunger skirt 851, the outer circumference 861 of the plunger skirt 851 is located at least partly outside of the corresponding circumferential edge 855 of the base plate 849. By transforming the plunger skirt 851 to the expanded state, it may be brought into contact with an edge portion 833 of the top sealing member 827 and be caused to press the edge portion 833 of the top sealing member 827 against the inside of the body wall 805.

If the can component attachment unit is provided with a transfer plate 529 comprising holding elements 534 as disclosed herein exerting an inwardly directed force on the can component, the plunger skirt 851 may contribute to press the can component back in a radial direction in case the can component does not spring back sufficiently itself from a deformed configuration imparted on the can component by the holding elements 534.

The positioning unit shown in FIG. 8 comprises a first piston 871 and a second piston 873 which is coaxial with the first piston 871. The pistons 871, 873 extend in an axial direction A, coinciding with the vertical direction z of the attachment unit 505, see FIGS. 5 and 6. The base plate 849 is attached to an end portion of the first piston 871, such that the footprint surface 853 is perpendicular to the axial direction A. The plunger skirt 851 is attached to an end portion of the second piston 873. The first and second pistons 871, 873 are configured to be moved in the axial direction A both together as a single unit, and as separate elements, independently of each other.

During displacement of the positioning device 828 into the intermediate can 803, the plunger skirt 851 remains in the unexpanded state until the can component 827 has been moved to the attachment position. When the can component 827 has reached the attachment position, the plunger skirt 851 is transformed to the expanded state by moving the end portion of the second piston 873 closer to the end portion of the first piston 871 thereby pressing an edge portion of the plunger skirt 851 radially outward.

The outer circumference 861 of the plunger skirt 851 presses the can component 827 against the inside of the body wall 805 of the intermediate can 803 which is placed in the positioning cavity. The edge portion of the outer circumference of the plunger skirt 851 which in the expanded state of the plunger skirt 851 is arranged to be in contact with and exert pressure on the can component, may have a contact surface which in the non-expanded state of the plunger skirt is slightly tilted with respect to the vertical direction of the positioning device.

In order to further improve contact between the can component and the can body material in the corner portions, thickened corner portions may be arranged on the upper surface of the base plate, i.e. on the surface opposite the footprint surface of the base plate. The thickened corner portions form raised areas on the upper surface of the base plate and serve to force the plunger skirt to move further out, exerting an increased pressure on the applied can component and improving contact between the can component and the tubular body. Thereby, a join formed between the can component and the corner portions of the tubular can body may be improved. In particular, an increased pressure in the corner portions of the tubular body may aid in creating a tight seal between the body material and a sheet form can component. Excess material present at the corner portions of sheet form can components, such as a bottom sealing member or a top sealing member, will generally wrinkle at the corners of the can as the can component is folded and aligned with the tubular body wall. In such case, an increased pressure created at the corner portions of the tubular body would compress the wrinkles and would contribute to the formation of a good functional bond, such as a thermo-weld between the body material and the sheet material in the can component. When using a thermo-welding process for bonding the can component to the wall of the tubular can body, at least one and preferably both of the can component and the tubular wall comprise a thermoplastic material in a sufficient amount to create a functional bond. 

1. A method for manufacturing a composite can and filling of dry or moist goods in said composite can, said method comprising: picking a body blank from a pile of body blanks and transferring said body blank to a body forming station; forming a tubular body by bending said body blank and bringing two opposing edges of said body blank together in an end-to-end join, said join extending in a height direction of said tubular body; sealing said join by welding a sealing strip over said join on an inner surface of said tubular body, thereby forming an intermediate can; transferring said intermediate can to a top sealing station; sealing a top opening at a top end of said tubular body by welding a peripheral flange of a top sealing member to said inner surface of said tubular body at a distance from a top end edge of said tubular body; transferring said intermediate can to a conveyor and placing said intermediate can on said conveyor a bottom opening at a bottom end of said tubular body facing upward in a vertical direction; transferring said intermediate can to a filling unit; filling said intermediate can with said dry or moist goods through said bottom opening of said tubular body; subjecting said intermediate can to a protective gas atmosphere either during said filling of said intermediate can or by introducing said filled intermediate can into a vacuum chamber to draw off air; transferring said filled intermediate can to a sealing unit, said filled intermediate can being transported to said sealing unit in a closed conveying system while maintaining said protective gas atmosphere; sealing said bottom opening of said tubular body by welding a peripheral flange of a bottom sealing member to said inner surface of said tubular body at a distance from a bottom end edge of said tubular body, sealing of said bottom opening being carried out while maintaining said protective gas atmosphere; turning said filled and bottom sealed intermediate can to bring said top end of said tubular body in an upward-facing position in said vertical direction and transferring said intermediate can to a lid attachment unit; and attaching a reclosable lid at said top end of said tubular body with an inner surface of said reclosable lid in direct contact with an upper surface of said top rim.
 2. The method according to claim 1, wherein the following steps are performed after sealing of said top opening: transferring said intermediate can to a top rim application station; applying a top rim to said intermediate can by inserting at least a lower part of said top rim into said top opening, above said top sealing member; welding said inserted part of said top rim to said inner surface of said tubular body; transferring said intermediate can to said conveyor and placing said intermediate can on said conveyor with said top rim resting on said conveyor and said bottom opening at said bottom end of said tubular body-R facing upward in a vertical direction;
 3. The method according to claim 1, wherein tightly fitted lead-in and outlet tunnels are arranged at an inlet and at an outlet of said sealing unit.
 4. The method according to claim 1, wherein said method comprises supplying a protective gas such as nitrogen, carbon dioxide or a mixture of nitrogen and carbon dioxide to said dry or moist goods during filling of said intermediate can and/or after filling of said intermediate can.
 5. The method according to claim 1, wherein said sealing unit is arranged in an external housing and is arranged to operate in a protective gas atmosphere in said external housing.
 6. The method according to claim 5, wherein an outlet port for said intermediate can is arranged in said external housing of said sealing unit-, wherein a size of said outlet port is adapted to a size of said intermediate can being processed.
 7. The method according to claim 6, wherein said outlet port comprises a short tunnel arranged at an end of an outlet conveyor member, wherein a stationary sliding plate constitutes a floor in said tunnel.
 8. The method according to claim 6, wherein an inlet port for said intermediate can is arranged in said external housing of said sealing unit- and a closable hatch is arranged at said inlet port.
 9. The method according to any one of the preceding claim 1, wherein said method further comprises: applying a bottom rim to said bottom end of said bottom sealed intermediate can; placing said bottom sealed intermediate can on a conveyor with said bottom rim resting on said conveyor-Rd) during said transfer of said intermediate can to said lid attachment unit.
 10. The method according to claim 1, wherein a scoop is applied between said top sealing member and said reclosable lid before attaching said reclosable lid at said top end of said tubular body, said scoop being applied directly on said top sealing member or being placed in a scoop holder which is arranged above said top sealing member.
 11. The method according to claim 1, wherein two or more intermediate cans are processed simultaneously during one or more of: sealing said top opening; applying said top rim; welding said top rim; filling said intermediate can; sealing said bottom opening; and attaching said reclosable lid.
 12. An assembly line for manufacturing of composite cans and filling of dry or moist goods in said composite cans according to the method of claim 1, said assembly line comprising a plurality of machine units connected by conveyors, wherein said machine units comprise: a body forming unit; a filling unit; a sealing unit; and a lid attachment unit.
 13. The assembly line according to claim 12, wherein a gas box is arranged between said filling unit and said sealing unit.
 14. The assembly line according to claim 12, wherein said sealing unit comprises a can sealing station and a rim application station.
 15. The assembly line according to claim 12, wherein said sealing unit is arranged in an external housing and is arranged to operate in a protective gas atmosphere in said external housing. 